To find the capacity of any tank in gallons: Square the diameter in inches, multiply by the length, and then by .0034.

In making patterns for aluminum castings provision must be made for shrinkage to a greater extent than with any other metal or alloy.

The toughness of aluminum can be increased by adding a small per cent. of phosphorus.

All alloys of metals having mercury are called amalgams.

A sheet of zinc suspended in the water of a boiler will produce an electrolytic action and prevent scaling to a considerable extent.

Hydrofluoric acid will not affect a pure diamond, but will dissolve all imitations.

A strong solution of alum put into glue will make it insoluble in water.

A grindstone with one side harder than the other can have its flinty side softened by immersing that part in boiled linseed oil.

One barrel contains 3 3/4 cubic feet.

One cubic yard contains 7 barrels.