The Sunday herald and weekly national intelligencer., 1890-04-20

attached teeth carved out of bone, which was
made to do passably good service; so says the
distinguished patient, in a letter to his dentist,
which is now preserved in museum, along
with the dentures named. The next advance in
this direction was making porcelain teeth,
mounted on gold or silver plates, struck up be-
tween metallic dies. But silver would not with
stand the action of the fluids of the mouth and
gold was too expensive for the masses. Then
about one-fourth century ago rubber was largely
substituted for gold on account of its cheapness
for dentures, but it was soon found to be
deleterious to health on account of being non
conductor, often producing congestion and in
fiammation to the mouth and throat.
Men of advanced thought in the dental pro-
fession, recognizing in aluminium the properties
Of lightness and strength, conductivity, and
purity, peculiarly fitting it for dental plate,
sought to use it for that purpose quarter of
century ago. but, alas! no one could solder it
as they did gold, or cast it successfully. The
difficulties in the way of casting aluminium are,
first, its extreme lightness, which precludes it
being poured when melted into a mould so as
to take fine sharp cast; and second, its great
contraction in cooling prevented it taking ac
curately the form of any desired model. After
a long conducted series of experiments DIR.
Carroll entirely overcome this difficulty by first
making the aluminium of commerce, which
always contains quite large per cent. OF iron
and silica, chemical pure, and then alloying it
with small per cent. Of royal metals that over
come the contraction. Then he devised an
automatic gas or gasoline furnace, with pneu-
matte crucible appliances, whereby the alumi-
mum is under perfect control when melted, and
can be forced by air into a matriX of any desired
form with perfect accuracy. Mr.. Richards, in
his valuable work on aluminium, published in
1887, said, "No one knows how to cast it," and
''that IL any one would take up the casting of
aluminium and bring it into vogue as a current
industrial operation there is no doubt that the
metal would be freely used in the finer branches
of practical mechanics"
This statement has been fully verified, as
shown by the increased demand which has
sprung up since the difficulties of working it
have been successfully demonstrated by the Car
roll methods. Thisincreased demand for alumni
mum has stimulated inventors and capitalists to
embark in this enterprise resulting in the pro-
duction of aluminium much cheaper and more
abundant, SO that instead of only few pounds
being produced and sold at a cost of $15 per
pound, as was the case two years since, now tons
are produced and placed upon the market at less
than two dollars per pound Until recently
France and England and Germany possessed the
made by the old W6hler and Deville sodium
process But history repeats itself, and now the
| suggestion of Davy of producing aluminium by
| electricity after lapse of nearly a century has
been made practical here in the United States
and large quantities are now being manufactured
very cheaply at Pittsburg, Pa, Newport, KY.
| also by the Carroll Aluminium Manufacturing
Company, of New York, with a branch office al
| Washington, ID. c., who claim to have the cheap
| est method yet invented of producing pure
| aluminium successfully. This company is or.
! ganized with a large capital for manufacturing
and utilizing aluminium in the arts, and propose
to manufacture cutlery, tableware, and many
other useful and ornamental articles from alumni.
mum. They are now supplying the s. s. White
! Dental Manufacturing Company, ii. ID. Justi
and other leading dental depots and dentists gen.
orally with their aluminium dental appliances.
They state that it will only be a short time at
the present progress being made in the produc-
| tiOn when the price of aluminium will be ae
cheap bulk for bulk, as iron, when its use will
no longer be confined to small articles, but will
be used in combination with or as a substitute
| for iron and steel wherever they are now used