These are much used for preserving fruits and vegetables. There are a
number of patent articles said to work well. They are, in our opinion,
more expensive, and more likely to fail in inexperienced hands, than
those that an ordinary tinman can readily make. The best invention for
general use is that that is most simple. Cans should be made in
cylindrical form, with an orifice in the top large enough to admit
whatever you wish to preserve, and should contain about two quarts. Fill
the cans and solder on the top, leaving an opening as large as a
pin-head, from which steam may escape. Set the cans in water nearly to
their tops, and gradually increase the heat under them until the water
begins to boil. Take out the cans, drop solder on the opening, and all
will be air-tight. This operation requires at least three hours, as the
heating must be moderate. You may preserve in glass bottles, filling and
putting in a cork very tight, and well tied, and gradually heating as
above; this will require four hours, as glass will be in danger of
bursting by too rapid heating. But for tomatoes, or anything that you
have no objection to boiling and seasoning before preserving, the best
way is to prepare and cook as for the table, putting in only pepper and
salt, and fill cans while the mass is boiling, and, with a sealing-wax
that you can get at any druggist's laid around the orifice, place the
cover upon it; the heat will melt the wax, and when it cools, the cover
will be fastened, and all will be air-tight. This will require no
process of slow boiling. Set the cans or bottles in a cool cellar, and
whatever they contain may be taken out, at the end of a year, as good as
when put in. The last method is the best and most simple of all. The
whole principle of preserving is to make the cans air-tight.