Dating science too
Produced during the era where all bottles were an relatively rare and cherished commodity to be discarded only when broken (i.e., the first third of the 19th century back many centuries prior) and does not otherwise fit the above two categories.
Utilitarian bottles include the majority of the bottles in the following bottle categories or types: soda, mineral water, beer, milk, proprietary medicine, druggist (excluding shop furniture), chemical, foods & sauces, household (including ink, shoe polish, cleaners, personal hygiene related items), common wine containers (excluding decanters), champagne, and most non-decanter spirits/liquor bottles.
)Reuse, of course, does not change the manufacturing date of the bottle itself, but care must be exercised when using the known date of one or a few bottles to date other items found from the same context.
When a likely or known "older" item is found in a known "newer" site it is referred to as deposition lag.
A substantial amount of bottle type specific information must be reviewed by a user to increase the probability of dating accuracy.
While running a bottle through the key questions, the user is frequently directed to move to other website pages to explain diagnostic features and concepts as well as to add depth and/or precision to the initial dating estimate.
Pontiled base fragments could also be from later produced "specialty" bottles which are described below.5.
Some bottle shapes are indicative of a particular manufacturing era, though many bottle styles/shapes were used for so many years - like the cylinder whiskey "fifth" or square snuff bottle - that the shape itself is not indicative of age.
Utilitarian items makes up the bulk of the bottles produced during the 19th century and first half of the 20th century. Bottles intended to be used once to dispense the contained product without much hope of return, though as noted in #4 above, many types of bottles were commonly reused during the 19th and early 20th centuries; or 2.
Heavy duty bottles intended to be recycled and reused by the producer or distributor of the contained product (primarily soda, beer & milk bottles); or 3.