| Mixtures | Temperature Changes in Degrees Fahrenheit | |
| From | To | |
| Common salt, 1 part; snow, 3 parts | 32 | zero .0 |
| Common salt, 1 part; snow 1 part | 32 | - .4 |
| Calcium chloride, 3 parts; snow 1 part | 32 | -27 |
| Calcium chloride, 2 parts; snow 1 part | 32 | -44 |
| Sal ammoniac, 5 parts; salt-peter 5 parts; water 16 parts | 50 | -10 |
| Sal ammoniac, 1 parts; salt-peter 1 part; water 1 part | 46 | -11 |
| Ammonium nitrate, 1 part; water 1 part | 50 | - 3 |
| Potassium hydrate, 4 parts; snow 3 parts | 32 | -35 |
IGNITION TEMPERATURES.
| Phosphorus | 120 | degrees | Fahrenheit |
| Bi-sulphide of carbon | 300 | “ | “ |
| Gun-cotton | 430 | “ | “ |
| Nitro-glycerine | 490 | “ | “ |
| Phosphorus, amorphous | 500 | “ | “ |
| Rifle powder | 550 | “ | “ |
| Charcoal | 660 | “ | “ |
| Dry pine wood | 800 | “ | “ |
| Oak | 900 | “ | “ |
POWER AND HEAT EQUIVALENTS.
In studying matters pertaining to power and heat, certain terms are used, such as horsepower, horsepower-hours, watts, watt-hours, kilowatt, kilowatt-hours, foot-pounds, joule, and B. T. U. (British Thermal Unit).
The following tables give a comprehensive idea of the values of the different terms:
| 1 Horsepower-hour | = 0.746 kilowatt-hour = 1,980,000 foot-pounds of water evaporated at 212 degrees Fahrenheit, raised from 62 degrees to 212 degrees. |
| 1 Kilowatt-hour | = 1,000 watt-hours = 1.34 horse-power-hours = 2,653,200 foot-pounds = 3,600,000 joules = 3,420 B. T. U. = 3.54 pounds of water evaporated at 212 degrees = 22.8 pounds of water raised from 62 to 212 degrees. |
| 1 Horsepower | = 746 watts = 0.746 kilowatts.= 33,000 foot-pounds per second = 2,550 B. T. U. per min. = 0.71 B. T. U. per second = 2.64 pounds of water evaporated per hour at 212 degrees. |
| 1 Kilowatt | = 1,000 watts = 1.34 horsepower = 2,653,200 foot-pounds per hour = 44,220 foot-pounds per min. = 737 foot-pounds per second = 3,420 B. T. U. per hour = 57 B. T. U. per min. = 0.95 B. T. U. per second = 3.54 pounds of water [p. 187] evaporated per hour at 212. |
| 1 Watt | = 1 joule per second = 0.00134 horse-power = 0.001 kilowatt = 342 B. T. U. per hour = 44.22 foot-pounds per min. = 0.74 foot-pounds per second = 0.0035 pounds of water evaporated per hour at 212 degrees. |
| 1 B. T. U. (British Thermal Unit) | = 1,052 watt-seconds = 778 foot-pounds = 0.252 calorie = 0.000292 kilowatt-hours = 0.000391 horsepower-hour = 0.00104 pounds of water evaporated at 212 degrees. |
| 1 Foot-pound | = 1.36 joule = 0.000000377 kilowatt-hour = 0.00129 B. T. U. = 0.0000005 horsepower-hour. |
| 1 Joule | = 1 watt-second = 0.000000278 kilowatt-hour = 0.00095 B. T. U. = 0.74 foot-pounds. |