28 



CALORIFIC POWER OF FUELS. 



ALEXEJEW'S CALORIMETER. 



The apparatus used by Alexejew was composed of a glass 

 combustion-chamber A (Fig. 6), in which he burnt the coal 



previously reduced to fragments. 

 These fragments were placed on a 

 platinum grating in the centre of 

 the chamber. The fuel was kindled 

 by means of a platinum sponge 

 placed over it, on which impinged 

 p^[( a jet of hydrogen from the gas- 



holder M t opening at c, correction 

 for which is of course made in the 

 calculation. The grating contain- 

 ing the fuel was suspended from 

 the glass rod a. As soon as the 

 combustion was started the current 

 of hydrogen was cut off by the cock 

 /, and the oxygen allowed to flow 

 in through b, the waste gases pass- 

 ing out through the coil. If the 

 combustion was interrupted, it was 

 rekindled by the hydrogen and 



platinum sponge. The hydrogen used was calculated in grams 

 and multiplied by 34500. The number of calories thus ob- 

 tained was deducted from that calculated from the rise in 

 temperature of the bath. According to Alexejew, the im- 

 portance of this correction never exceeded one-half per cent, 

 and he never had to rekindle the fuel. 



Alexejew did not determine the unburnt gases, as experi- 

 ence showed they never exceeded 0.35 per cent. It is im- 

 possible, however, to determine the hydrogen of the hydro- 

 carbons if desired, as these would be mixed with the hydrogen 

 used for kindling, part of which may escape combustion. 

 The kindling with hydrogen might, however, be replaced by 

 that with carbon, as in the F. & S. apparatus. 



FIG. 6. ALEXEJEW CALORIM 

 ETER. 



