Bottle Dating

Grouping of bottle dating from the 1840s to the 1930s.

Machine-made bottles portion
of the Dating Key

HOME: Bottle Dating: Machine-made bottles

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General Machine-made Diagnostic Features:  Machine-made bottles will exhibit most or all of the diagnostic characteristics explained and illustrated below.  (This summary is largely an amalgam of Toulouse 1969b; Miller & Sullivan 1981; Jones & Sullivan 1989; Boow 1991; Cable 1999; Miller & McNichol 2002; Miller & Morin 2004; empirical observations.)  It should be noted that features #1, #3, #4, #5, and #6 are primary indicators of machine-made manufacture.  Feature #2 (mold seam diameter) is not as strongly diagnostic as the primary indicators as mouth-blown bottles sometimes can have very fine mold seams.  Feature #7 describes a couple glass related features that are quite consistent in machine-made bottles, but not diagnostic, i.e., mouth-blown bottles may sometimes have few/no bubbles in the glass and even thickness:

A machine-made beer bottle; click on image to view an illustration of the same bottle pointing out the machine-made diagnostic features.

Click on the machine-made beer bottle picture above to see an illustration of this bottle showing the major diagnostic characteristics of a typical machine produced bottle.

1.  Vertical side mold seams which usually (see the Note box below point #3 for an exception) run up to the highest point of the finish and often onto the extreme top finish surface (i.e., onto the rim or lip).  On most early and many later machine-made bottles the vertical body/neck and finish mold seams are frequently (but not always) discontinuous and offset from each other; click offset seams for a picture of this attribute.  These vertical seams - finish mold seams vis-à-vis the upper neck mold seams - may range from just slightly offset to 90 degrees offset (like shown at the linked image above).  This is a function of the orientation of the parison relative to the two (parison and blow) molds used on the particular machine.  There are also no horizontal tooling marks present on the finish and/or upper neck as would be observable on the finish of mouth-blown bottles.

2. The side mold seams on most machine-made bottles tend to be finer (narrower and lower) -  though sometimes sharper and/or visually distinct than mouth-blown bottle mold seams although many mouth-blown bottles have very thick and distinct seams due to less precise mold construction or fitting.  The statement about machine-made bottles may seem contradictory (finer but more visually distinct) but is a function of the higher machine blowing pressure.  Earlier machine-made bottles (1905-1920s) tend to have somewhat thicker/higher mold seams than later machine-made bottles due to the increasing precision in mold machining and machinery in general as time progressed.  Most machine-made bottles have mold seams about the thickness of a hair while most visible mouth-blown mold seams tend to be several times as thick, higher, but more rounded.  (Mold seam thickness and how high it protrudes [height] is of only moderate use in telling a machine-made bottle from a mouth-blown bottle, though if a bottle fragment has a hair fine mold seam, it is highly likely to be from a machine-made bottle.)

3. There are at least two additional finish related mold seams - one at the top of the finish which encircles either the bore or sometimes the outside of the upper lip portion of the finish (sometimes both of these seams are present) and a horizontal seam immediately below the finish which circles the extreme upper neck (called a "neck ring parting line").  Click on the picture to the left to view an illustration which shows both of these seams or click machine-made finish to view an image which shows well the seam below the finish.  Both seams are quite diagnostic of machine manufacture and are usually visible, though the seam at the top of the finish can be hard to see on some bottles - especially if the finish was fire polished.  In the glassmaking trade, these seams along with the side mold seams within the finish or just below are referred to as "neck ring" or "neckring" seams since they were formed by the separate neck ring portion of a machine mold (Tooley 1953).

Note: There are a few machine-made bottle types (milk and small ink bottles) or post-production processes (fire polishing) which exhibit mold seams in the finish/upper neck that deviate from the descriptions in points #1 and/or #3 above; these bottles may appear to be of mouth-blown manufacture.  These deviations are discussed on the main Bottle Dating page in a box under Question #2.  Click Exceptions to Question #2 to view this discussion.

4.  "Ghost" seams are usually present on the neck, shoulder, and/or body of the bottle if made by a blow-and-blow machine (like the Owens Automatic Bottle Machine).  These are faint, somewhat wandering, hairline seams which if present (usually) are sporadically visible on the sides of machine-made bottles.  The ghost seams are caused by the parison mold parts and if visible enough will be "attached" to the vertical seams in the finish.  Click on ghost seam to view a close-up explanatory picture of this attribute.  Be aware that bottles and jars made by early to mid-20th century press-and-blow machines do not usually have ghost seams, since the parison mold was usually one-piece, but will typically have a valve mark on the base (see #6 below).

5.  A suction scar is present on the base of Owens Automatic Bottle Machine produced bottles.  This distinctive base scar is easier to illustrate than describe; click on suction scar for a picture of a typical scar which exhibits the diagnostic "feathering" that surely indicates Owens machine production (same image is below left).  This mark is distinctive to the suction process which feeds glass into the bottom of an Owens machine's parison mold.  (Note: A movie clip showing this process in action is linked at the bottom of this box.)  Suction scars can not be produced by feed and flow automatic machines (i.e. "gob feeders") though a similar type mark without the feathering is induced by the parison/blank mold of most other blow-and-blow machines - including up to the present day.  Press-and-blow machines usually have a round valve mark on the base but lack either the suction or parison scars.  In any event, the suction scar is never found on mouth-blown bottles though suction scars are sometimes referred to as a pontil scar by the unfamiliar.  See the machine-made section of the Bottle Bases page for more information on these scars.  (Note:  It is likely that other types of suction based automatic bottle machines made in Europe in the 1920s - and possibly later - also produced a suction scar on the base of their products [Pearson 1928].  However, a large majority of bottles in the U. S. with distinct suction scars were likely Owens machine produced.)

6. The presence of a circular valve mark on the base of a bottle (typically a wide mouth bottle or jar) is sure evidence of machine-made manufacture by a press-and-blow machine.  This is discussed further as Question #14 below. 

7.  Machine-made bottles tend to have few if any bubbles in the glass and the thickness of the glass is usually more uniform throughout the bottle as compared to mouth-blown bottles.  This is especially true of later machine made bottles, i.e. from the late 1920s on.  (Note: The presence or absence of bubbles in the glass and relatively even distribution of the glass throughout the characteristic is not a primary feature of either machine-made or mouth-blown bottles, though there are strong trends

(For more details about the production of machine-made bottles visit the machine-made bottles section of the Glassmaking & Glassmakers page.)

Owens suction scar on the base of an Owens Bottle Company product; click to enlarge.What these Diagnostic Features Indicate:  Bottles with all the noted primary machine-made characteristics (#1, #3-#5) including the suction scar on the base (point #5 above and picture to the left) can date no earlier than 1905 and are usually post-1910.  Though patented and first used to a limited degree in 1903, the first Owens Automatic Bottle Machine licenses were granted to other manufacturers in late 1904 making 1905 the effective "beginning" (i.e., terminus post quem) date for bottles with all of the above listed machine made diagnostic characteristics (Miller & McNichol 2002).  Bottles which have all the primary characteristics noted above (#1, #3, #4) without the suction scar (#5) were produced by non-Owens automatic or semi-automatic machines and are somewhat harder to precisely date, though the vast majority post-date 1905 also. 

Narrow neck press-and-blow machine?

It should be noted that one fairly early press-and-blow semi-automatic machine was designed to produce narrow bore bottles.  It was noted in 1910 that the Cumberland Glass Company (Bridgeton, NJ) had "...succeeded in perfecting a machine that will satisfactorily produce narrow neck bottles, such as catsups, beer bottles, etc., at a big saving over the hand method."

The method used was unusual and may have been unique in bottle-making history:  "The machine differs from all others, and in getting the neck upon the bottle, the vessel is made in two sections, the neck being put upon the bowl with a second operation. This is accomplished so that there is no perceptible mark upon the bottle showing the joint, and the bottle stands every possible test as to strength. The machine is operated much as all pressing machines are..." (National Glass Budget 1910; Lockhart pers. comm. 2007). 

Although products of this machine are not conclusively known a bottle such as the one at this link - offset seams shoe polish bottle - may well be a product of the described machine as there is a distinct and abrupt interface edge at the shoulder where the mold seams for both the body and neck end and are offset.  This little bottle has a moderately narrow neck and a distinct valve or ejection mark on the base indicating press-and-blow machine manufacture.  Added evidence to this theory is that an identical shape and size (2 oz.) "Round Shoe Polish" bottle is shown in the "Machine Made Ware" section of Cumberland's 1911 catalog (Cumberland Glass 1911).

More specifically, non-Owens machine-made bottles with narrow necks (similar to the amber beer bottle pictured earlier) will always date after 1908 (and typically after 1910) regardless of what type machine they were produced on since the first blow-and-blow semi-automatic machines capable of producing narrow necked bottles (copied after English machines invented somewhat earlier) were first made or used at that time in the U.S. (Boow 1991; Cable 1999).  Very few narrow neck bottles made on the Owens machines will pre-date that time also.  Bottles or jars with wide mouths (like the jar pictured under Question #15 below) may occasionally pre-date 1905, to as early as about 1893, since semi-automatic press-and-blow machines were being used to some degree by the mid-1890s.  (The first production bottles known to have been made on semi-automatic machines were wide mouth Vaseline bottles made by the C. L. Flaccus Glass Co. [Beaver Falls, PA.] in 1894 [Lockhart et al. 2007d].)  It is thought that probably all pre-1905 semi-automatic bottle machine production in the U.S. was relegated to wide-mouth bottles/jars due to limitations of the press-and-blow machines at that time (Toulouse 1967; Miller & Sullivan 1981; Jones & Sullivan 1989; Cable 1999; Miller & McNichol 2002; Lockhart pers. comm. 2003).  

The 1908 photo below is from the Lewis Hine collection (Library of Congress) and shows an early, probably O'Neill (Barrett 2011) semi-automatic press-and-blow 4 mold milk bottle (which have relatively wide mouths) machine which came with the following caption:  "Machine that blows 4 milk bottles at a time. No "lung blowers" employed. Travis Glass Co., Clarksburg W. Va. Manager says machines are fast coming into play in bottle industry, plans eventually to have machines in place of "carrying in boys." Location: Clarksburg, West Virginia" (Library of Congress).  This two table semi-automatic machine would have been hand fed with glass (furnace likely to the right) and does have the two different mold sets with the parison molds (where the first "press" part of the cycle took place) the set on the right.  Blowing air would have been supplied by the hose visible at the top of the set of blow molds to the left, where the final "blow" part of the cycle took place.

O'Neill milk bottle machine in 1908; click to enlarge.This image (click to enlarge) also shows that on many early press-and-blow machines the parison mold was one-piece (note absence of mold hinges) as the narrow non-inflated parison could be removed from either the base or finish mold end (depending on the type machine) whereas the blow mold had to be two-piece (hinges obvious) to remove the expanded and finished bottle if there was any narrowing from the body to the neck/finish (like a typical milk bottle would have).

A review of Illinois Glass Company catalogs from the early 1900s shows that wide mouth bottles apparently made by semi-automatic "Machine Made" methods first appear in the 1906 catalog and were not present (or at least specifically noted)  in catalogs before that time.  As the Illinois Glass Company was one of the largest glassmakers of the time it is reasonable to assume that semi-automatic machines producing wide mouth bottles/jars became common throughout most of the glass industry about that same time.  This allows for a high probability begin date of around 1900 to 1905 for most wide mouth, machine-made bottles and jars (Illinois Glass Company 1903, 1906, 1908).  However, since the products of automatic and semi-automatic non-Owens machines date from the same era as the Owens machine and are largely indistinguishable, they are all considered together on this machine-made bottle dating page.

Mouth-blown to Machine-made Transition Era:  The transition from mouth-blown to machine-made bottles was a fairly long and circuitous road.  There were numerous reasons why machines were not immediately accepted - some of which follow (taken primarily from Toulouse 1967, 1969a & 1971):

- The expense of licensing and acquiring an automatic bottle machine was quite high, pricing most smaller glassmakers out of the market.  Between 1905 and about 1914 or 1915, the only fully automatic machine was the Owens Automatic Bottle Machine and until the late 1910s they were granting exclusive licenses for various categories of bottles.  In about 1915, reliable gob-feeders became available which converted most types of semi-automatic machines to fully automatic at a lower cost than the Owens Machines.

- Many of the glass companies that did acquire fully automatic bottle machines retained hand operations for smaller or specialty orders for quite some time.  For instance the Carr-Lowery Glass Company (Baltimore, MD) began automatic bottle making in 1915, but retained some hand-blowing operations until at least 1971 when Dr. Toulouse published Bottle Makers and Their Marks!

- Worker opposition to machines delayed their introduction in many glass operations.  In one glass factory a wall had to be erected between the hand operations and the newly installed machine to prevent sabotage.  In another instance, worker opposition was so strong that the machine operations were abandoned!

A pair of Groves Chill Tonic bottles with different manufacturing histories; click to enlarge.Regardless of the obstacles, the proportion of machine-made to hand-blown bottles increased dramatically after 1905 so that by 1917 no more than about 10% of the bottles and jars produced in the U.S. were mouth or hand-blown; 90+% were produced by automatic and semi-automatic methods and would exhibit typical machine-made characteristics.  The total number of bottles produced in the United States also dramatically rises from 7,777,000 gross in 1899 (all mouth-blown) to 24,000,000 gross in 1917, most of which were machine made (Barnett 1926; Miller & Sullivan 1981).  These numbers help to determine general dating break probabilities for both machine-made and mouth-blown bottles.  For example, given the incredible quantities of bottles produced by machines after 1917 through the mid-20th century, a bottle with machine-made characteristics - especially with a narrow neck/mouth -  is highly likely to have been made later than the mid-1910s.  Likewise, the probability that a bottle exhibiting mouth-blown (hand-made) diagnostic features dating prior to the mid-1910s is very high and after the 1920s is very low, though not impossible as noted above.

The link below allows a user to view an amazing short movie clip that shows two different early Owens Automatic Bottle Machines in operation.  The first machine is the "Machine #5" which the film clip script notes as having been made in 1906 in Toledo, Ohio.  This was apparently the earliest of the viable commercial machines, and in fact, the clip was made to help promote and sell the machine to potential buyers.  The first person shown operating Machine #5 is Emil Bock, a mechanical genius who worked with Michael Owens from the "bicycle pump" early machine experimentation days (1890s) and transformed Mike's ideas into workable steel machines.  Michael Owens is the second person shown picking up and examining a couple beer bottles.  This clip is also reported to be the only movie ever made showing Michael Owens who was reputed to be "camera shy."  The last half of the clip shows a much larger, 15 head "AQ" machine in operation at an Owens-Illinois plant in 1959 (Walbridge 1920; Owens-Illinois Co. 1959; Perry pers. comm. 2007).  Of particular note, the 1959 portion of the clip shows  the sucking up and cutting off of the glass from the continuous tank by the parison or blank mold.  Towards the end it also shows the shift of the parison from the parison/blank mold to the blow mold.  Film clip is compliments of the Owens-Illinois Glass Company. (Many thanks to Phil Perry - a senior engineer with that company - who graciously provided this clip.) 

Film clip of an early Owens Automatic Bottle Machine in operation.


Machine-made Bottle Dating

As with mouth-blown bottles, more precise dating of a machine-made bottle can be done with some confidence by using one or more of the various diagnostic features outlined in the questions on this page.  Unlike the first portions of the Dating key (Questions #1 through #3 on the main Bottle Dating page; #4 through #7 on the Mouth-blown bottles portion of the dating key), each question on this page is an independent dating tool for which the response is not predicated on the outcome of any of the other questions.  Thus, these questions do not have to be viewed in order.  The question numbers on this page continue where they left off on the mouth-blown bottle portion of the key.


Question #8:  Is the bottle glass color aqua (aquamarine or very light green), essentially colorless (clear), or a color other than colorless or aqua?

Question #9:  Are there "bubbles" present in the glass?  If so, how many and what size/shape?

Question #10:  Does the bottle have the following statement embossed on its side or on the base?  FEDERAL LAW FORBIDS SALE OR REUSE OF THIS BOTTLE

Question #11:  Does the bottle base have similar markings to those on the bottle pictured? (These markings are those of the Owens-Illinois Glass Company.)

Question #12:  Does the bottle have a finish (lip) that was sealed with a cork, sealed with an externally threaded screw cap, or sealed with some other type closure?

Question #13:  Does the bottle have what appears to be a painted or enameled label, lettering, and/or decoration? 

Question #14:  Does the bottle have a shallowly incised circle on the base that is (usually) between 1/3" to 3/4" (10-18mm) in diameter?

Question #15:  Does the bottle have a narrow mouth (bore/finish) or does it have a wide mouth (bore/finish)?

Question #16:  Does the bottle have embossed (or labeled) contents or volume capacity information?

Question #17:  Does all or a portion of the bottle base have a textured pattern, i.e., stippling or knurling?

Question #18: Does the bottle have any type of glass/bottle makers markings embossed on the base (typically) or body (occasionally)?

Read through each of the questions to see which have pertinence to the bottle you wish to date.  Hyperlink to other web pages that are suggested in each question for added information and then read the summary statement at the end of this page which will give some suggestions on where on this website a user could or should proceed to.  Keep track of the specific diagnostic feature date ranges listed in each question you consult, and once to the end of the page, use that information to ascertain the likely production date range of your bottle.  See dating examples #1, #4, & #5 on the Dating Examples page for guidance.

As explained previously above, be aware that the 1905 "earliest" date used in the questions is not absolute.  There were some wide mouth, semi-automatic machine produced bottles (albeit a very low percentage) which had machine-made characteristics (minus a suction scar) than can date back as early as the mid-1890s. 

Lets begin with Question #8 right below...

QUESTION #8: Is the bottle glass color:

    A. Aqua (aquamarine or very pale green);
    B. Essentially colorless (clear); or
    C. A color other than colorless or aqua?

The color of the glass in a machine-made bottle can, to a limited degree, be useful in dating.  (As with all of the dating points on this page, color must be considered in conjunction with other diagnostic characteristics in arriving at a probable date or date range for any given bottle - the "preponderance of evidence" concept.)  With the increasing dominance of the automatic bottle machine in the 1910s and on, bottle shapes, sizes, and colors became more and more standardized and uniform, i.e. much less variety.  Glass making technology progressed so that colorless (aka "clear") glass became much cheaper to produce and displaced aqua as the dominant bottle glass color for containers where being able to see the products natural color was an important consideration.  An assortment of other colors were still common - particularly amber and to some degree, cobalt blue - but the range of common colors present in machine-made bottles was restricted compared to bottles produced in the 19th century.  See the Bottle/Glass Colors page for more information on this fascinating subject.


Small wide mouth bottle with slight amethyst tint.
Bottle made from manganese dioxide decolorized glass exhibiting a slight lavender cast in the thick portions of the glass.  Small utility bottle - ca. 1910-1920.

Beverage bottle with a slight straw color cast to the glass.
Bottle made from arsenic and/or selenium decolorized glass exhibiting a slight "straw" color cast in the thick portions of the glass - Beverage bottle - ca. 1920-1925.

A. Bottle made of aqua glass A machine-made bottle made of aqua glass - which is not a soda bottle or canning jar - is most likely to date from or prior to the 1920s. 

Click on Groves Chill Tonic to view a picture of an aqua medicinal from the 1910-1920 era.  (The bottle pictured in Question #9 below with a plethora of bubbles in the glass would be considered a particular deep shade of aqua.)  The amount of aqua glass bottles produced declines throughout this period so that by the mid to late 1920s the dominant colors for machine-made bottles (excluding soda bottles and canning jars) is colorless or amber.  Aqua pretty much disappears by the early 1930s as a bottle color with the notable exception of soda bottles (and many canning jars) which continued to be produced in various shades of aqua up until recent years (Miller & McNichol 2002,2010; empirical observations).  Royal Crown Cola, Dr. Pepper (both a greenish aqua), and Coca-Cola ("Georgia Green") are familiar examples of late era aqua bottles (Toulouse 1971).  For more information on this color, click aqua to go to its description on the Bottle Colors page.

B. Bottle is of largely colorless (aka "clear") glass
Machine-made bottles with colorless glass can date from any time after 1905, though there is a relatively reliable dating break possible based on the type of colorless glass.  In the production of colorless glass numerous methods - mechanical, physical, and/or chemical - were used to decolorize glass (Tooley 1953).  Decolorizing is in essence neutralizing the effects of the iron and carbonaceous impurities in the glass mix in order to obtain as colorless of glass as possible.  The primary physical (masking) agents used in the first half of the 20th century were manganese dioxide, selenium, and arsenic.  All potentially leave a very slight residual color to the glass that is usually visible when looking closely at the thickest portion of the base or sides.  For more information click colorless glass to go to that section of the Bottle Colors page.

Manganese dioxide causes the glass to have a very slight lavender or amethyst tint which is amplified to varying degrees with exposure to sunlight (or artificial radiation).  Manganese oxide was found to be difficult to work with - particularly in the open glass furnaces used for the Owens Automatic Bottle Machine - and was eventually overshadowed by selenium and arsenic for decolorizing (Miller & Pacey 1985).  When selenium or arsenic (or a combination of the two) is used to decolorize glass, it often leaves a very faint "straw" cast to the thick glass portions which is not affected or intensified by sunlight.  (Note: It has been thought for many years that selenium produced the "straw" cast to otherwise colorless - and almost exclusively - machine-made bottles.  However, it is now thought to be a function of using arsenic - probably in tandem with selenium - as the decolorizer [Tooley 1953; Lockhart pers. comm. 2003].)  The following dating refinements are possible with colorless machine-made bottles:

1. The large majority of machine-made bottles with a slight to moderate lavender or amethyst tint - indicating manganese oxide was used as the decolorizer - date between 1905 and the early 1920s (top picture above right; click small amethyst wide-mouth bottle for a picture of this entire bottle) though some can date as late as the 1930s.  Machine-made soda bottles were generally not decolorized with manganese after 1914 (Lockhart 2006a).

2. The large majority of machine-made bottles with a pale "straw" color tint (bottom picture above right) - indicating selenium and/or arsenic use as a decolorizer - will date no earlier than 1912 (Lockhart 2006a & b).  Based on empirical observations, one or both of these decolorizers are still in use today although after the 1960s other decolorizing agents and glass producing processes were used resulting in less abundant "straw" tinted bottles.

C. Bottle made of some other color of glass
If the bottle has some other glass color no useful general dating information is possible.  However, some bottle-type specific dating refinement is possible based on specific glass colors for both machine-made and mouth-blown bottles; see the Bottle/Glass Colors and Bottle Typing/Diagnostic Shapes pages for more information.   Move to the other questions below for more dating opportunities.

QUESTION #9:  Are there "bubbles" present in the glass?  If so, how many and what size and shape?

Mid-20th century Mexican bottle exhibiting 19th century diagnostic manufacturing features.
Bubbles in the shoulder glass of a bottle.  This is an extreme example of the number of bubbles to be found in a bottle.  Click on the picture to see more of this bottle,  which is one of the many exceptions in the use of bubbles (and several other diagnostic features) to date an item.  This is a Mexican made liquor bottle intended for the U.S. market - ca. mid-20th century.

"Bubbles" are air or gas filled cavities within the glass.  The image to the left is a close-up of a bottle with bubbles in atypically high quantity for illustrative purposes.  Bubbles are caused by an assortment of irregularities in the production process including a glass pot or tank that was too hot or not full enough, glass cut-off or shearing irregularities, and various gob feeder problems.  In the glass making industry, small bubbles were referred to as "seeds" and larger bubbles as "blisters" (Tooley 1953).   Similar to the color question above, the presence of bubbles in the glass can help some in pinning down the date of a machine bottle, but must be used in conjunction with other features to more confidently narrow down a date range as it is not conclusive by itself. 

Some authors - most notably Jones & Sullivan (1989) - believe that "the number and size of bubbles has absolutely no connection with the age of the glass."  This appears quite true of mouth-blown bottles, though empirical evidence suggests some dating trends with regards to machine-made bottles.  More specifically, there appears to have been an increase in the homogeneity and uniformity of glass as the technological advances of the machine era proceeded.  However, this feature is still a tenuous one since there are many early machine-made bottles with few or no bubbles.  Conversely, machine-made bottles after the 1920s which have numerous and/or large bubbles exist but are rare (Girade 1989; Lockhart pers. comm. 2003).  See the Bottle Body Characteristics & Mold Seams for more information on bubbles.

As a general rule of thumb, earlier machine-made bottles and jars (i.e., 1905 to 1910 [mid-1890s for wide mouth ware] through the 1920s) will have more and larger bubbles than later machine-made bottles (early 1930s and later) when bubbles in the glass became a much rarer occurrence due to ever more refined glassmaking technology.  Larger bubbles (~1/8" and larger) and/or numerous bubbles of all sizes are more prevalent in bottles manufactured during the early machine period - 1890s (wide mouth ware) to early 1920s.  The absence of bubbles or presence of only a very few small "seed" bubbles (less than a pin-head in size) or very narrow "V" shaped bubbles, denotes a bottle that is more likely to date from or after the 1930s.   (The "V" shaped bubbles are discussed on the Bottle Body Characteristics & Mold Seams page.) 

If one takes a look at glass bottles found in supermarkets today they would be hard pressed to find even one bubble in all the bottles looked at combined as technology has all but eradicated this flaw in glassmaking.

  Does the bottle have the following statement embossed on its side or on the base?


Mid-20th century liquor flask with the Federally required embossed statement.
FEDERAL LAW FORBIDS SALE OR RE-USE OF THIS BOTTLE inscription on the shoulder of a machine-made pint liquor flask manufactured in 1956 by the Owens-Illinois Glass Company.  This embossing was legally required on all liquor bottles sold in the U.S. between 1935 and 1964.

In the U.S., National Prohibition was repealed in late 1933 and was subsequently followed by the passage of Federal laws prohibiting the reuse or sale of used liquor bottles.  This requirement was intended to discourage the re-use of bottles by bootleggers and moonshiners, though the biggest discouragement to that illicit activity was that liquor was now legally available.  On January 1st, 1935 all liquor sold in the United States was required to be in bottles that had the above statement embossed in the glass (Busch 1981).  The statement was not required on wine or beer bottles, the latter category which was - and to some degree still is - bottled in re-useable bottles. 

If your bottle has this statement embossed in the glass, it is a machine-made liquor bottle that dates between 1935 and the mid-1960s.  This inscription is found only on machine-made bottles, with the rare exception of some Mexican-made (for the U. S. market) bottle being mouth-blown during that era.

In 1964, the law requiring this statement was repealed.  Be aware however that for some years after 1964, liquor could still be found in bottles with this phrase since not all liquor producers switched immediately to new bottles due to the expense of new molds or to deplete an existing supply of bottles (Ferraro 1966)  Click 1974 liquor bottle to view a picture of the base of a liquor bottle which has the reuse prohibition embossing though was made well after (10 years) the regulations requiring the statement were eliminated.  The linked bottle was made by the Thatcher Glass Manufacturing Company (Elmira, NY.) and has a date code for 1974.  The company used the stylized "TMC" mark from 1949 to 1985 (Toulouse 1971; Giarde 1989; Whitten 2005).

If your machine-made bottle does not have this phrase embossed in the glass it is probably either not a spirits or liquor bottle, made outside the era the statement was required, or the bottle was originally sold outside the U.S.  If you know the bottle is a U. S. made/sold spirits bottle (i.e. distinctly a spirits bottle in shape or design or it has other conclusive features like brand embossing or labeling) it could date prior to 1935, though is more likely to be a post-1964 product.  A pre-1935 date is possible since some spirits - particularly whiskey and brandy - were available to a limited degree by prescription through pharmacists to be used "for medicinal purposes only."  Most pre-Prohibition (pre-1920) liquor/spirits bottles exhibit mouth-blown manufacturing characteristics, i.e., they are uncommonly machine-made.  This is because Prohibition occurred individually in most states between 1912 and 1918, with National Prohibition finally passed in 1919 and effective in early 1920.  This time span was the peak changeover from hand to automated bottle production methods.  Visit the liquor bottle section of the Bottle Typing/Diagnostic Shapes page for more information on spirits bottles.

NOTE: Some references and many people believe that there are liquor bottles embossed with FEDERAL LAW PROHIBITS SALE OR RE-USE OF THIS BOTTLE, i.e., PROHIBITS instead of the word FORBIDS (Ferraro 1966).  No PROHIBITS bottles have ever been observed by the author or other consultants to this website and it is believed to be a myth, though the author would welcome conclusive proof (an image) that PROHIBITS was indeed used in this context.

Note about a potential related dating refinement.
After National Prohibition ended (1933) various regulations were implemented in regards to the bottling of liquor/spirits, e.g., the required embossing noted above.  Another requirement was specific liquor bottle permit numbers assigned to individual glass companies and specific factories which were authorized by the Federal Government to produce liquor bottles.  These numbers were embossed on the base of many (maybe all?) liquor bottles produced in the U. S. during the mid-20th century and can be a useful tool for determining who made the bottle.  A listing of these permit numbers by glass company/plant can be found at this link:  Industry Liquor Bottle Permit Numbers  (This listing courtesy of Russ Hoenig, Owens-Illinois Glass Co. [retired].)  This can often lead to enhanced dating refinement of mid-20th century liquor bottle depending on the current information available for the glass maker.  See this websites makers marking page at this link - Glass Making & Glass Makers: Bottle & Glass Makers Markings - for articles on scores of glass companies. 


  Does the bottle base have similar markings to those on the bottle pictured below?

Beer bottle base showing typical Owens-Illinois makers markings.
This picture shows the "Diamond O-I" makers mark inside the white box (click to enlarge).  Pictured is a beer bottle made at the Owens-Illinois Glass Co. plant in Oakland, CA. in 1941.

Bottles with the highlighted mark in the image date between 1930 and the mid-1950s (with some limited use of this mark until at least 1959).

The "Diamond O-I" makers mark of the Owens-Illinois Glass Co. is shown in the picture within the white box (click to enlarge).  This mark is also called the "Saturn" mark by some due to its stylized resemblance.  (Note: The "O" in the Diamond O-I marking is actually a vertically elongated oval, although referred to here as an "O" for simplicity.)  This makers mark is very common on bottles made during the 1929-1930 to mid-1950s period as the company was (and still is) a dominant force in the bottle production world at that time (Toulouse 1971; Lockhart 2004d). 

The various Owens-Illinois markings provide an opportunity to also identify which plant made the bottle and in what year.  Specifically for the pictured export beer bottle, the script Duraglas marking and the stippling (molded "roughness") around the outside edge of the base were both used first in 1940, so this bottle can date no earlier than that.  The "1" to the right of Diamond O-I mark is the year code and in this case obviously can not be earlier than 1941 (i.e., not 1931) because of the Duraglas embossing and stippling.  In the early 1940s, realizing that single digit date codes were repeating (e.g., "0" could be 1930 or 1940), caused the company to add a period after the single digit on some bottle types - primarily soda bottles (not beer bottles) - from about that time to the mid-1940s.  At that point two digit year codes (e.g., "46" for 1946) were used on most bottles types; in particular, beer, soda and milk bottles.  Unfortunately, the use of the one and two digit date codes was inconsistently used by different plants and mold makers so this is not a certain rule for dating. 

For example, the illustrated bottle was highly likely to have been made in 1941  since one made in 1951 would likely have a date code of "51."  The "20" to the left of the Diamond O-I mark is the code for the Oakland, CA. plant* which began operations in 1936 and is still in operation today - so knowing the factory is of no use in pinning down the manufacturing date.  Similarly, the bottle is paper labeled as having been used by the Columbia Brewing Inc. (Tacoma, WA.) who did business under that name from 1934 to 1953 when it became the Heidelberg Brewing Co. (Van Wieren 1995).  Once again though, this bit of information does not help pin down the date.  The clincher for the 1941 date is the heavier (thicker) glass that this particular bottle was made with identifying it as having been made just prior to the wartime reduction in the amount of glass used for many bottle types as a conservation effort during WWII.  This bottle is also an example of how even with the relatively ample amount of information Owens-Illinois bottle bases provide, one may still need to rely on more than one piece of data (e.g., plant codes, brewery dates of operation/business) to ensure a reliable manufacturing date determination (Toulouse 1971; Lockhart 2004d; Phil Perry, O-I engineer pers. comm. 2007; Lockhart pers. comm. 2007,2011).  (More on this bottle is found on the Beer & Ale Bottles Typology page.)

Owens-Illinois mark from 1960; click to enlarge.Between 1954 and about 1959 the Owens-Illinois Glass Co. changed the Diamond O-I marking to a simpler "I in an O" mark (same basic mark minus the elongated diamond) although the time of this change varied through the noted period depending on the specific plant, mold life, and possibly bottle type.  The base image to the right is of this newer mark on a bottle made at plant #21 (Portland, OR.) in 1960 - the first year of operation for the Portland plant (Toulouse 1971; Girade 1989; Lockhart 2004d)*.  Date codes with this later mark (still in use today) are variable with both single and double digit codes (like in the image) observed, though recently made beer bottles (1990s and later) seem to consistently have two digit codes (empirical observations). 

For a discussion of the Duraglas marking - shown on the amber beer bottle base above - see Question #17 below.  For more information on Owens-Illinois marks, see Bill Lockhart's Bottles and Extras article reproduced at the following link (pdf file): Owens-Illinois Glass Company (Lockhart 2004d).

*A listing of the specific numbers associated with the dozens of different Owens-Illinois Glass Company plants from 1929 to the present is available on this website at the following link: 
Listing of Owens-Illinois Glass Co. plant numerical codes - 1929 to present 
This table is a useful addendum to Bill Lockhart's 2004 Owens-Illinois Glass Co. article linked above.

When present, bottle makers marks can be an excellent tool for helping with the dating of historic bottles.  Since there were so many different makers markings on both mouth-blown and machine-made bottles, they are not covered in this key.  Makers marks are discussed more on the Bottle & Glass Maker's Markings page.

Illustration of cork type finish from a 1928 Owens Bottle Company prescription bottle catalog.

Illustration of a screw top bottle from a 1928 Owens Bottle Company prescription bottle catalog.

The top illustration shows a cork finish (i.e. cork accepting) on a prescription druggist bottle.  The bottom illustration shows the same type bottle with a screw thread finish with the metal cap on.  Illustrations from a 1928 Owens Bottle Company "Want Book and Catalog of Owens Bottles...for Druggists".  This catalog shows the availability of both closure types from the same manufacturer in the late 1920s with the note that the screw caps are "...growing more popular every day."  The company (now named Owens-Illinois Glass Co.) still offered cork finishes on prescription bottles at least until 1935, though much diminished in importance in their catalogs.

 Does the bottle have a finish (lip) that was:

    A. Sealed with a cork;
    B. Sealed with an externally threaded screw cap; or
    C. Sealed with some other type closure?

The cork finish versus screw-thread finish can be helpful in dating machine-made bottles but only allows for a moderately accurate dating break which to a large degree is bottle type specific.  Cork is still commonly used for sealing bottles containing wine and champagne, occasional liquor/spirits bottles, and rarely some specialty food product bottles. 

The utility here for dating is that certain types of bottles made the transition from cork accepting to screw-thread finishes during the mid-1920s through the 1930s; see 1928 illustrations to the right.  The bottle types that made the switch during this era are the majority of medicinals, food, and ink bottles; most liquor/spirits bottles; and some non-alcoholic, non-carbonated beverage bottles.  (If the type bottle you have is in doubt as to its likely use, visit the Bottle Typing/Diagnostic Shapes page for identification information.)

External screw thread finish on a 1920's catsup bottle.
External (continuous) screw threads on a Heinz™ catsup bottle produced by the Illinois Pacific Glass Company (San Francisco, CA.) - ca. 1925-1930.

External screw-threads were first used during the mid-19th century though almost exclusively on canning jars including the famous Mason's "1858" jar.  By the 1890s and early 1900s external screw-threads were being used occasionally on mouth-blown liquor/spirits bottles & flasks, some commercial food bottles, ink bottles, and other bottle types more rarely.  The use of screw threads was still limited by the lack of precision in hand production processes.  These older external screw thread bottles would likely have keyed out as mouth-blown in Question #2 because of the ground lip surface present on most mouth-blown external screw-thread bottles.

External screw threads became more common as fully automatic bottle machines dominated over hand production methods, since machines produced much more uniform and precise finish dimensions allowing for standardized caps.  External screw-threads came to dominate closure types by the Depression (1930s), except on soda and beer bottles.  For more information go to the Types of Bottle Closures page and/or the Types of Bottle Finishes page, both of which provide much more information on this complex subject including the distinctly different types of screw threads.

A. Cork style finish - The bottle you have has a finish that accepted a cork as the closure and is not a soda, beer, wine/champagne, or liquor bottle.  Cork closure, machine-made medicinals, food, inks, and some non-alcoholic beverage bottles usually date prior to the early 1930s, though there are numerous exceptions.

Generic 1932 medicinal bottles with plastic caps; click to enlarge.Plastic caps for external threaded finishes: an excellent bottle dating feature.

Plastic caps for screw thread finishes can be an excellent tool for dating.  Bakelite - an early thermosetting plastic - made its debut in 1927 as a screw cap closure material though was first patented in 1907 (Berge 1980).  This provides a terminus post quem (earliest date of use) of 1927 for bottles with the plastic cap still present.  The bottle illustrated is from a 1932 Owens-Illinois Glass Co. (Toledo, OH.) druggist bottle catalog and clearly shows what they call a "molded cap" on a "prescription ware" bottle.

B. External ("screw") thread finish - The bottle you have has external screw threads - which are usually either continuous or non-continuous or variations on these themes.  Most all types of machine-made bottles with external screw threads date from the late 1920s or after, though some types - like catsup bottles - were commonly screw-threaded from the beginning of machine manufacture in the early 1910s.

C. Other closure/finish type - There are a lot of finish styles that accepted crown caps, lightening stoppers, or other types of closures which do not resemble either of the choices here.  If your bottle does not fit "A" or "B" above, you will need to visit other site pages like Bottle Finishes & Closures and/or Bottle Typing/Diagnostic Shapes for more information.


QUESTION #13:  Does the bottle have what appears to be a painted or enameled label, lettering, and/or decoration? 

Applied color label on a 1946 soda water bottle from Oregon.
Applied Color Label (ACL) on a 10 oz. soda bottle from the Mission Bottling Co., Klamath Falls, Oregon. Bottle made by the Owens-Illinois Co. Oakland, CA. plant in 1946.

Applied color labeling or lettering (also known as ACL or pyroglazing) was a common way of permanently labeling or owner marking a bottle without the use of fragile paper labels.  It was most common by far on soda and milk bottles, but can occasionally be found on other types of bottles.  The ACL process is explained on the Bottle Body Characteristics & Mold Seams page.  See the image to the right for an example of a simple two "color" (black and white) ACL soda bottle.

An ACL soda or milk bottle dates no earlier than 1934, when the ACL process was first adopted for commercial use in the United States (Girade 1989), with almost complete acceptance by bottle makers (and users) by the early 1940s (Lockhart pers. comm. 2003).  Many beverage and some other types of bottles are still produced today with ACL's (e.g., Corona™ Beer) providing no termination date for this feature. 

(Note: It should be pointed out that embossed milk and soda bottles continued to be made well after similar ACL versions were dominating the market, with embossed milk bottles made into the 1950s and soda bottles into the 1960s and later [empirical observations]).


QUESTION #14:  Does the bottle have a shallowly incised circle on the base that is (usually) between 1/3" to 3/4" (10-18mm) in diameter? 

Close-up view of a valve mark on the base of an 1930's milk bottle from Nevada; click to enlarge.

A valve or ejection mark on the base of a bottle is a definitive indication of machine-made manufacture by a press-and-blow type machine (Miller & Morin 2004).  This mark was formed by machines that utilized a push-rod valve to eject the partially expanded parison out of the one-piece blank mold (the "press" part of the process) to be grasped by "transfer tongs" when shifting the parison to the second blow mold (the "blow" part of the machine process) (Tooley 1953).  To view illustrations of how press-and-blow machines operated and how the valve/ejection mark was formed, click on the following links which are of the Lynch Milk Bottle machine cycle:  press-and-blow machine cycle - stages 1-3; press-and-blow machine cycle - stages 4-7.

A valve mark is usually perfectly round and roughly 1/2" inch (12-14 mm) in diameter though can occasionally be a bit smaller (10-12 mm) or larger (up to at least 24 mm).  The circle is incised or sharply indented into the surface of the glass and can be distinctly felt by running ones fingernail over the mark.  On somewhat rare occasions (by a few different glass companies) the valve rod had a mold number incised in it which would emboss the base of the bottle with this number when ejecting the parison; these numbers will always be centered in within the ejection mark (Lockhart pers. comm. 2007; empirical observations).

Blake-Hart base view; click to enlarge.Valve marks are almost exclusively found on wide mouth machine-made hollow ware - food bottles & jars, milk bottles, and canning/fruit jars.  These  are all types of bottles generally made by press-and-blow machines.  Toulouse (1969b) noted that this mark is "...most often found on wide mouth foods of the 1930s and 1940s and even later, and on many milk containers."  The mark is indeed most commonly observed on wide mouth milk bottles and food jars made between the early 1900s through the 1940s, and occasionally after that.  It is also very common on canning jars, including many that were produced by semi-automatic press-and-blow machines possibly as early as 1898 (Birmingham 1980; Leybourne 2001).  The milk bottle pictured above is covered on the Bottle Dating Examples page.  The square milk bottle base pictured dates from the mid to late 1920s and is discussed at this link: Blake-Hart patent milk bottle.

Valve marks are very unusual on narrow necked/mouth (bore) bottle types though there are some exceptions as valve marks are occasionally seen on early (1910s) machine-made beer and soda bottles.  At least one manufacturer (Cumberland Glass Manufacturing Company, Bridgeton, NJ) invented and used a type of semi-automatic press-and-blow machine in 1910 which did produce narrow neck bottles that most likely resulted in a valve mark on the base of the bottles produced in the early 1910s (Lockhart pers. comm. 2006; Peters pers. comm. 2007).  Thus, the presence of a valve mark on a soda or beer bottles would indicate a narrow manufacture date in the early 1910s.

QUESTION #15:  Does the bottle have a narrow mouth (bore/finish) or does it have a wide mouth (bore/finish)?

Ecomony finish without the closure; click to enlarge.During the mid-1890s, semi-automatic machines began to be used for the production of bottles and jars.  The first production bottles known to have been made on semi-automatic machines were wide mouth Vaseline bottles made by the C. L. Flaccus Glass Co. in 1894 (Lockhart et al. 2007d).  For the first decade or so of use (i.e. up to about 1905) semi-automatic machines were useful almost exclusively for the production of wide mouth bottles and jars (picture to the left) due to the limitations of the press-and-blow machines in use at that time.  Because of this, non-Owens machine-made bottles (see "General Machine-made Diagnostic Features" point #5 at the beginning of this page) with narrow necks- like the medicinal bottles pictured below right - will essentially always date after 1905 and virtually always after 1910.  This also largely holds true for narrow-mouth bottles made by the Owens machines which did not really begin to dominate bottle production until about 1908-1910 (Toulouse 1967; Miller & Sullivan 1981; Jones & Sullivan 1989; Boow 1991; Miller & McNichol 2002; Lockhart pers. comm. 2003).

A review of Illinois Glass Company catalogs from the early 1900s shows that wide mouth bottles - certainly made by semi-automatic "Machine Made" methods - first appear in the 1906 catalog and were not present in catalogs before that time.  Since the Illinois Glass Company was one of the largest bottle producers of the time it is reasonable to assume that the semi-automatic machines producing wide mouth bottles/jars became common throughout most of the glass industry about that same time.  This allows for a high probability begin date of around 1900 to 1905 for most wide mouth, machine-made bottles and jars (Illinois Glass Company 1903, 1906, 1908).A pair of Groves Chill Tonic bottles with different manufacturing histories; click to enlarge.  Click on the following links to see all of the pages from the 1906 Illinois Glass Company catalog that show their machine-made items:  pages 278-279; pages 280-281; pages 282-283; pages 284-285; pages 286-287.  The types of bottles illustrated on these pages would be considered typical of the earliest machine-made bottles in the U. S., i.e., from the late 1890s to around 1910.  Most other types of bottles still would have been mouth-blown during this same era.  To summarize:

See the Machine-made bottle section of the Glassmaking & Glassmakers page for more information on machine-made manufacturing via press-and-blow (and other) machines.


QUESTION #16:  Does the bottle have embossed (or labeled) contents or volume capacity information?

Late (1910s) mouth-blown bottle with capacity embossing; click to enlarge.It was very uncommon until the early 20th century for the capacity or volume of the contents of a bottle to be noted in the embossing or on the label (or closure sometimes).  The image to the right shows a very late mouth-blown druggist bottle (1914 to early 1920s) from Spokane, WA. that has the volume capacity ("12 oz.") embossed on the shoulder.  The origin of volume designations is explained in an article by Bill Lockhart dealing with El Paso, TX. soda bottlers published in The Artifact in 2003; part of which is quoted below.  (Note: This article was also re-published in Bottles and Extras in 2006 (Lockhart 2006a) and available at this link: A Tale of Two Machines and A Revolution in Soft Drink Bottling.)

On March 3, 1913, Congress passed H. R. 22526, generally known as the Gould Amendment to the Pure Food and Drug Act of 1906. Although the Pure Food and Drug Act demanded a great deal of labeling information, it did not require the inclusion of volume specification. The Gould Amendment corrected that oversight when it stated that the "quantity of the contents be . . . plainly and conspicuously marked on the outside of the package in terms of weight, measure, or numerical count" but continued to explain that "reasonable variations shall be permitted." Although the law went into effect immediately, it clarified that "no penalty of fine, imprisonment, or confiscation shall be enforced for any violation of its provisions as to domestic products prepared or foreign products imported prior to eighteen months after its passage" (U. S. 1913:732). In other words, the industry actually had a grace period in required compliance until September 3, 1914.

In order to be in compliance with the Gould Amendment, soda bottlers in El Paso (along with those in the rest of the U. S.) had to include volume information on their containers by no later than September 1914. All bottles bearing volume data can therefore be dated as no earlier than 1913 and probably not until 1914. Thus far, I have found no datable, mouth-blown, El Paso soda bottles containing volume information. However, a few machine-made bottles from both the Magnolia Coca-Cola Bottling Co. and the Empire Bottling Works, El Paso’s two largest bottlers at that time, contain no volume information. This suggests that they were produced prior to the Gould Amendment or at least no later than 1914. All other machine-made bottles that I have examined, filled by El Paso bottlers, bore volume information.  (Lockhart 2003, 2006)

Given this information, it appears that the majority of machine-made (and some mouth-blown items like pictured above) beverage, food, and medicinal bottles with embossed (or labeled) specific capacity or volume information likely date from 1913 or later.  This information is of no use for bottles without volume embossing with no label still present or for bottles that did not hold a beverage, food, or medicinal product, all of which were regulated by the Pure Food and Drug Act of 1906. 

One notable exception to the above is that many earlier machine-made liquor/spirits and milk bottles had volume notations embossed in the glass (e.g., "QUART," "FULL QUART," "ONE PINT," etc.) or on the label as early as 1900-1905, though the large majority of machine-made bottles with capacity information date from the 1913 law or after.  Click "FULL PINT" embossed flask to see an example of an relatively early (1919) machine-made liquor flask that is embossed with FULL PINT on the shoulder.  Volume notation on liquor bottles was apparently a marketing issue and seems to be related to the rise of mail-order liquor which is briefly discussed under the Tall, slender bodied, straight neck spirits cylinders (late 19th & 20th century) section on the Liquor & Spirits Bottles page.  The use of volume notations on earlier milk bottles was likely associated with the demands for more cleanliness, reliability, and predictability of the product once home delivery began to be popular in the early 1900s (though reportedly began in 1878).  See the milk bottle section of the typology pages for more information.

Question #17:  Does all or a portion of the bottle base have a textured pattern, i.e., stippling or knurling?

The bases of mid to late 20th century, machine-made bottles very commonly have a textured effect covering all or a portion of the base - see the image to the left.   There were several practical reasons for this feature: the bottles would have a reduced base surface contact decreasing drag on the conveyor belts moving them within the factory and by purchasers/users; to hide product related sediment; to hide the suction scar (primarily on Owens Automatic Bottle Machine products); and for at least one specific machine operational reason (Phil Perry, engineer with the Owens-Illinois Glass Co., pers. comm. 2010).  The noted conveyor belt utility would only involve the stippling on the resting surface of the bottle base - like that on the 1941 beer bottle base below where the stippling pattern is just on the outside base edge where contact would occur.  Various stippling patterns were also added to bottle bases for largely esthetic reasons, such as the 1959 green soda bottle base to the left.  None of the stippling - given the indented nature of the base center and lack of stippling on the resting surface - would have come in contact with the conveyor belt.

Base of an Owen-Illinois produced beer bottle.Stippling is shown on both the bottle bases in the images and was typically produced by hand punching the base plate of the bottle mold.  Knurling was machine impressed on the base plate.  Practically speaking for the purposes of this website, the difference between the two is unimportant and the precise "look" of these base designs varies quite a bit over time, with different bottle types and between bottle makers.  Click knurled base to see such as defined by a Owens-Illinois engineer (Phil Perry, pers. comm. 2010) on a bottle that is date coded most likely for 1959.  (The above and linked photos courtesy of Carol Serr.)  Other types of base perimeter stippling resembles small crescents - (((((((( - which is very common on modern beer bottles.  Another design commonly seen on the base perimeter of late 20th century and modern wine bottles is like this: ( )( )( )( )( ).

It is not precisely certain when this feature first originated although it likely first appeared in 1940 on bottles produced by the Owens-Illinois Glass Company when they began using their proprietary "Duraglas" bottle making process (Toulouse 1971).  Both of the pictured bottle bases note such with the script Duraglas on the base.  This likely terminus post quem is supported by date codes noted by the author and others on bottles made by that company (Lockhart 2004d; empirical observations).  So if one has a machine-made bottle with a stippled base one can be quite certain that it dates from 1940 or later.

As a side note, the Duraglas in upper and lower case script as shown in the images dates the bottle from between 1940 to possible as late as 1963.  DURAGLAS in all capital block letters dates after 1963 to some point that the company dispensed with it altogether - probably in the 1970s (Toulouse 1971; empirical observations).  This inscription is only seen on Owens-Illinois Glass Co. products.


QUESTION#18:  Does the bottle have any type of glass/bottle makers markings embossed on the base (typically) or body (occasionally)?

Base of an Owen-Illinois produced beer bottle.Machine-made (and often mouth-blown) bottles will very frequently have embossing on the base (image to the right and the most common location), heel, and/or body which identifies the actual manufacturer of the bottle.  Be aware that many times the embossing on a bottle base is not a manufacturers or "makers mark" but instead is either related to the product the bottle contained, the user of the bottle, or is for internal manufacturer related tracking (e.g., mold or catalog designations) of little use in dating or typology. 

When present, however, makers marks - in hand with answers to the other questions noted prior - will often allow for a distinct narrowing of the date range in which a given bottles was likely produced.  For example, the mark to the right inside the white box is the ubiquitous marking used by the Owens-Illinois Glass Company from 1929 or 1930 until the mid to late 1950s (ending time dependent on the bottle type and/or production factory).  This bottle actually dates from 1941  as discussed in Question #11 above.  As one can see, when present makers marks can be one of the best dating tools of all!

To assist with this endeavor please consult the Bottle & Glass Makers Markings page which contains links to scores of articles posted on this website which were largely produced by members of the Bottle Research Group (BRG)These articles deal with specific makers markings and the history of the companies behind those markings.  This will be a "work-in-progress" over the coming years as scores more BRG articles (including revisions and updates of past articles) are planned to be "e-published" via this website on an array of other bottle makers.

In order to make full use of this comprehensive  information, however, one has to know what mark or marks were used by what glass or bottle manufacturing company.  If not known and the marking is either a clearly identifiable alphabetical letter or letters (like A. B. Co. for the American Bottle Company) or a distinct logo or symbol, a user must first determine the origin of that makers marking.  This can be done by using the appropriate "Makers Markings Logo Table" to ascertain which mark/marks were used by what company.

Makers Markings Logo Tables (preliminary drafts)


Once a makers marking is identified one can go to the Bottle & Glass Makers Markings page (link below) to (hopefully) find the glass makers article that pertains to the mark, if an article does exist for that particular maker.

Click the following link to go directly to that listing of makers marking articles:
Bottle Makers Articles 


This completes the portion of the key that deals with machine-made bottles and is the end of the key for diagnostic bottle dating.  Consider the answers and dating overlap information provided by the above questions together in arriving at a likely age range for your bottle.  For some examples of how to use this information to refine your date range see the Dating Examples  page.

As with the mouth-blown bottles, there are a number of other physical attributes of bottles that can variably allow for more precise dating.  These features, however, tend to be accurate at a bottle type or category specific level and/or are impossible to incorporate into a simple key. 

From this point a user must consult other pages for additional information on a given bottle.  The titles of (and links to) all of the pages contained within this site can be viewed by clicking on Website Map.  Peruse the titles to see if any may help with your quest for information.  It is suggested, however, that a user first consult the Bottle Typing/Diagnostic Shapes page for bottle type identification which includes additional bottle category specific dating information.  From that page the user will also be directed to other potentially useful website pages.  Happy hunting!


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ill Lindsey
Bureau of Land Management (retired) -
Klamath Falls, Oregon
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