3O CALORIFIC POWER OF FUELS. 



of the crucible escaped at b. The thermometer / showed 

 whether the temperature of the gases was the same as that 

 of the bath. 



The calorimetric bath contained 1500 grams (3.3 Ibs.) of 

 water, and was protected against external influences by a 

 wood casing, while the space C was filled with glass wool; 

 but this is not necessary, n is a brass cover which may be 

 dispensed with. The thermometer T is the calorimetric 

 thermometer; m is an agitator moved by the string o. The 

 value in water of the one used by Fischer was 113.5 calories. 

 The coal was dried in nitrogen. The carbonic acid and the 

 unburnt carbon were determined. 



THOMSEN S CALORIMETER. 



This calorimeter was designed especially for tests of gases 

 and vapors. It is not adapted to tests of solid fuels. It 



consisted (Fig. 8) of a calorimetric 

 bath of thin brass, with a capacity 

 of some 3 litres (195 cubic inches), 

 protected from radiation by a cylin- 

 drical ebonite envelope ; and a plati- 

 num balloon of half a litre (32.5 

 cubic inches) capacity, in which the 

 gases were burnt, being delivered 

 through the opening at the bottom. 

 The waste gases passed off 

 through a coil, and a mechanical 

 agitator kept the water in circula- 

 tion. 



The dried gas was delivered 

 with perfect regularity from a mercury gas-holder, sufficient 

 air or oxygen being added to render it free-burning, and 

 enough oxygen was supplied to insure perfect combustion. 

 This he attained by always having 40 to 50 per cent in the 



FIG. 8. THOMSEN CALO- 

 RIMETER. 



