The Dictionary Of Photography

A True Historic Record Of The Art & Practice Of Photography 100 Years Ago.

Home | About | Photography | Contact






Thermometer and Thermometry
Thermometer &nd Thermometry. The thermometer is an instrument used for determining the temperatures of different substances, liquids, and gases. These instruments are so gene-rally known that but little description is needed; but, as several different methods of marking them are in vogue, the following explanation and rules may make all clear: - There are three principal methods of division - Reaumur, Celsius or Centigrade* and Fahrenheit. Reaumur takes oo as the temperature of freezing water, and divides the scale between this point and boiling water into 8oo. This system is generally dying out. Centigrade, or Celsius' system, has oo as the freezing point and iooo as the boiling point. This system is gradually gaining ground. Fahrenheit's system has 32^ as the freezing point and 2120 as the boiling point. This is the system in common use in England. To convert degrees of one scale into those of another the following rules must be used: -
See Absolute Temperature.
609                              RR