glass jars, but in spite of this they are coming into extensive use. The
kind that may be used without any special equipment has a tin lid that
fits into a groove and is fastened in place with rosin or sealing wax.
Some cans, however, require that the lids be soldered in place. While
soldering requires special equipment, this method of making the cans
air-tight is the best, and it is employed where considerable canning is
done, as by canning clubs or commercial canners.

[Illustration: FIG. 5]

In the purchase of tin cans, the size of the opening should receive
consideration. If large fruits and vegetables, such as peaches, pears,
and tomatoes, are to be canned, the opening must be a large one;
whereas, if peas, beans, corn, and other small vegetables or fruits are
to be canned, cans having a smaller opening may be chosen. When acid
fruits or vegetables are to be canned, use should be made of cans that
are coated with shellac, as this covering on the inside of the cans
prevents any action of the acid on the tin.

* * * * *

CANNING METHODS

GENERAL DISCUSSION

26. The methods employed for the canning of foods include the
_open-kettle method_, the _cold-pack method_, the _steam-pressure
method_, and the _oven method_. Of these, the open-kettle method is
perhaps the oldest household method of canning, and it is still used by
many housewives. The other methods, which are newer, seem troublesome to