A little tidbit that may come in handy someday, from American
Cookery, October 1925.

"The number of tablespoons in a package of gelatine depends on the
brand, or the process of manufacture. It may be said that it
depends on the package. As a general rule, the package of
gelatine contains enough to stiffen two quarts of liquid. Finely
granulated gelatine makes a less bulky package than that which is
coarser. In our own experience we have known different brands to
measure for one-fourth to one-half cupful of the dry gelatine,
while each of them was advertised to yield two quarts of jelly.
Consequently, it comes nearer right to follow the recipe that
prescribes 'one-half package' when the one who framed the recipes
does not know which of the many brands of gelatine will be used by
the one who follows it."
--
Jean B.