PRELIMINARY REPORT ON PEAT. 
299 
The ash, fixed carbon and volatile matter (other than water) 
together add up to 100% in each case. The sulphur and nitrogen 
are part of the volatile matter determined separately. The per¬ 
centages of ash and fixed carbon added together give the amount 
of coke which may be obtained from each sample, for in the 
process of coking enough heat is used to drive off all the other 
ingredients. 
The fuel value is given in "‘British thermal units” per pound. 
A British thermal unit is the quantity of heat required to raise 
the temperature of a pound of water one degree Fahrenheit, or, 
to be more precise, from 50° to 51 0 F. If the fuel value is given 
as 10,000 B. T. U., for instance, this means that a pound of the 
material if burned under the most favorable conditions could be 
made to raise the temperature of 5 tons of water i°, or : ton 5°, etc. 
