blowpipe as easily as a
carpenter saws off a board. With such a flame he can carve out a pattern
in a steel plate in a way that reminds me of the days when I used to
make brackets with a scroll saw out of cigar boxes. The torch will
travel through a steel plate an inch or two thick at a rate of six to
ten inches a minute.

[Illustration: Courtesy of the Carborundum Company, Niagara Falls

MAKING ALOXITE IN THE ELECTRIC FURNACES BY FUSING COKE AND BAUXITE

In the background are the circular furnaces. In the foreground are the
fused masses of the product]

[Illustration: Courtesy of the Carborundum Co., Niagara Falls

A BLOCK OF CARBORUNDUM CRYSTALS]

[Illustration: Courtesy of the Carborundum Co., Niagara Falls

MAKING CARBORUNDUM IN THE ELECTRIC FURNACE

At the end may be seen the attachments for the wires carrying the
electric current and on the side the flames from the burning carbon.]

The temperatures attainable with various fuels in the compound blowpipe
are said to be:

Acetylene with oxygen 7878 deg. F.
Hydrogen with oxygen 6785 deg. F.
Coal gas with oxygen 6575 deg. F.
Gasoline with oxygen 5788 deg. F.

If we compare the formula of acetylene, C_{2}H_{2} with that of
ethylene, C_{2}H_{4}, or with ethane, C_{2}H_{6}, we see that acetylene
could take on two or four more atoms. It is evidently what the chemists
call an "unsaturated" compound, one that has not reached its limit of
hydrogenation. It is therefore a very active and energetic compound,
ready to pick up on the slightest instigation hydrogen or oxygen or
chlorine or any other elements that happen to be handy. This is why it
is so useful as a starting point for synthetic chemistry.

To build up from this simple substance, acetylene, the higher compounds
of carbon and oxygen it is necessary to call in the aid of that
mysterious agency, the catalyst. Acetylene is not always acted upon by
water, as we know, for we see it bubbling up through the water when
prepared from the carbide. But if to the water be added a little acid
and a mercury salt, the acetylene gas will unite with the water forming
a new compound, acetaldehyde. We can show the change most simply in this
fashion:

C_{2}H_{2} + H_{2}O --> C_{2}H_{4}O

acetylene _added to_ water _forms_ acetaldehyde

Acetaldehyde is not of much importance in itself, but is useful as a
transition. If its vapor mixed with hydrogen is passed over finely
di