xial bodies, with two of their axes equal,
have the same surface for the unit weight.

For example:

Size Length Surface Weight Surface for 1 lb.
2 in. Sq. 12 in. 96.0 sq. in. 13.60 lb. 7.06 sq. in.
2 in. Round 12 in. 75.4 sq. in. 10.68 lb. 7.06 sq. in.

Although this discussion is at present based upon mathematical
analysis, it is hoped that it will open up a new field of investigation
in which but little work has been done, and may assist in settling
the as yet unsolved question of the effect of size and shape in
the heat treatment of steel.

HEAT-TREATING EQUIPMENT AND METHODS FOR MASS PRODUCTION

The heat-treating department of the Brown-Lipe-Chapin Company,
Syracuse, N. Y., runs day and night, and besides handling all the
hardening of tools, parts of jigs, fixtures, special machines and
appliances, carburizes and heat-treats every month between 150,000
and 200,000 gears, pinions, crosses and other components entering
into the construction of differentials for automobiles.

The treatment of the steel really begins in the mill, where the
steel is made to conform to a specific formula. On the arrival
of the rough forgings at the Brown-Lipe-Chapin factory, the first
of a long series of inspections begins.

ANNEALING METHOD.--Forgings which are too hard to machine are put
in pots with a little charcoal to cause a reducing atmosphere and
to prevent scale. The covers are then luted on and the pots placed
in the furnace. Carbon steel from 15 to 25 points is annealed at
1,600 deg.F. Nickel steel of the same carbon and containing in addition
3-1/2 per cent nickel is annealed at 1,450 deg.F. When the pots are
heated through, they are rolled to the yard and allowed to cool.
This method of annealing gives the best hardness for quick machining.

The requirements in the machine operations are very rigid and, in
spite of great care and probably the finest equipment of special
machines in the world, a small percentage of the product fails
to pass inspection during or at the completion of the machine
operations. These pieces, however, are not a loss, for they play
an important part in the hardening process, indicating as they do
the exact depth of penetration of the carburizing material and
the condition of both case and core.

HEAT-TREATING DEPARTMENT.--The heat-treating department occupies an
L-shaped building. The design is very practical, with the furnace
and the floor on the same l