As soon as cans were introduced on the market, can-openers appeared. The
flurry of can-opener  patents  should provide some dating tools.
 
While the configuration of the can may be used to determine its contents,
or its date, one should remember that anachronisms abound in the can
industry. A personal acquaintance, who is very much alive, worked in a
Spanish cannery after World War II, filling cans of the hand-soldered types
that were used in America before 1900. If one should find her handiwork, a
nineteenth-cntury date would be presumed. The Richardson and Robbins
cannery in Dover, Delaware, employed can makers, hand-building tapered plum
pudding cans, in my memory (and I am not that old!). The tapered cans could
have been made by machine methods, but the plant had no retirement program,
and the old can makers just made cans til they fell over.  R&R had been one
of the first to introduce the ham-shaped ham can, and was an early user of
the key opened can, which was seen as a boon for picnickers who forgot to
bring a patent can opener.
 
There are several excellent studies of cans and can making that could be
used to further interpret these fascinating artifacts, but the last word
has by no means been spoken on the subject.
 
Here are a few sources>
 
Barbara J. Wade
1978
Manufacturing typology for tin containers from the Arctic Salvage Project
Parks Canada Manuscript Report 299
 
Mary B. Sim
1951
Commercial Canning in New Jersey: History and Early Development
New Jersey Agricultural Society, Trenton
 
Arthur J Cox and Thomas Malin
1984
Ferracute: History of an American enterprise
Privately published in Bridgeton, New Jersey
 
Arthur I. Judge, editor
1914
A history of the canning industry
Canning Trade, Baltimore
(Most of the historical statements currently repeated in secondary sources
have been drawn from this source.)
 
Jane Busch
1981
Introduction to the tin can
Historical Archaeology 15:95
 
Edward F. Heite
1990
Archeological data recovery on the Collins, Geddes Cannery Site
DelDOT archaeological series 83
(Begging a thousand pardons for blowing my own tin horn)
 
 
  _______
. |___|__\_==
. | _ |  | --]   Ned Heite,                ><DARWIN>
. =(O)-----(O)=  Camden, DE 19934           / \  / \
---------------------------------
"Baby" Series IIA 88" 2.25L petrol Land Rover (3 main bearing)
Explore Icelandic wool:  http://www.dmv.com/~iceland---------
Recent research:  http://home.dmv.com/~eheite/index.html ----
-------------------------------------------------------------