The cubical expansion, or expansion of volume, of water, from 32° F. to 212° F. and upwards, is given in the following Table. The rate of expansion increases with the temperature. The expansion for the range of temperature from 32° to 212° is .0466, or fully 4½ per cent, of the volume at 32°; or an average of .000259 per degree, or 1 / 3863 part of the volume at 32° F.

Expansion of Liquids from 32° to 212° F. Volume at 32° = 1.

 Volume at 212°. Expansion. Alcohol. 1.1100 1/9 Nitric acid. 1.1100 1/9 Olive oil 1.0800 1/12 Turpentine 1.0700 1/14 Sea water........ 1.0500 1/20 Water. 1.0466 1/22 Mercury 1.018 1/56

## Friction

The ratio obtained by dividing the entire force of friction by the normal pressure is called the coefficient of friction. The unit or coefficient of friction is the friction due to a normal pressure of one pound:

Iron on oak...................

Cast iron on oak...............

Oak on oak, fibres parallel......

Oak on oak, greased...........

Cast iron on cast iron..........

Wrought iron on wrought iron. . .

Brass on iron.................

Brass on brass................

Wrought iron on cast iron......

Cast iron on elm...............

Soft limestone on the same.....

Hard limestone on the same. . . . Leather belts on wooden pulleys. Leather belts on cast-iron pulleys Cast iron on cast iron, greased. ..

0.62 0.49 0.48 0.10 0.15 0.14 0.16 0.20 0.19 0.19 0.64 0.38 0.47 0.28 0.10

Pivots or axes of wrought or cast iron, on brass or cast-iron pillows:

First, when constantly supplied with oil. Second,when greased from time to time. Third, without any application........

0.05 0.08 0.15