maintain their integrity, but became crumbly and
granular.

For conducting properties it ranks about with tin, and fillings can be
made more rapidly than with cohesive gold. We have used ounces of it,
but time has proved that everything that can be done with it in filling
teeth can also be accomplished as well and in some cases better with tin
foil.

In 1878 Dr. N. B. Slayton patented his Felt Foil, which was said to be
tin cut into hair-like fibers by a machine, then pressed into small
sheets and sold in one-half-ounce books, but it sold only to a very
limited extent. Soon after this Dr. Jere Robinson, Sr., invented a
machine and began the manufacture of a similar article, but he found he
was infringing on the Slayton patent, so he purchased the Slayton
machine and made satisfactory terms to continue his own manufacture of
fibrous material. After this little was heard of Slayton's Felt Foil,
but Robinson's was considerably used. The two materials look and are
manipulated almost exactly alike. Dr. Robinson has both of
above-mentioned machines now in his possession.

Archibald McBride, of Pittsburg, Pa., in 1838, made a roll of a portion
of a sheet of tin, and then used just enough gold to cover it, aiming
to keep the gold on the surface, so as to have the filling look like one
of all gold, and not with the idea of deriving any special benefit from
the effects of wear or preservation as obtained by thus combining the
two metals. The fee for a gold filling was one dollar; tin, fifty cents.
Some operators have advocated using tin and gold (symbol Tg), rolled or
folded together in alternate layers, thus exposing both metals to the
fluids of the mouth; claiming that fillings can be made quicker, are not
so subject to thermal changes, and can be inserted nearer the pulp than
when gold is used. This may be true in comparison with gold, but these
three claims are entirely met by using tin alone. Others say that this
union of gold and tin will preserve the teeth as well as a correct gold
filling, making no conditions or restrictions as to tooth-structure or
location of cavity. They say that it preserves the cervical margin
better than gold; that it expands _slightly_.

A description of some different methods of combining and manipulating
tin and gold is subjoined:

(_a_) Two sheets of No. 4 cohesive gold and one of the same number of
tin are used; place the tin between the gold, cut off strips, and use
with hand or mallet