404 Mr. Richardson on the' Composition of Coal. 



76 c c azote reduced to 0° thermometer and 28° barometer give 70-4 c c, which is equal 

 to 32-24 per cent. From the analysis of Liebig, this acid contains 33-36 per cent., so that 

 there is a loss of 1-12 per cent. 



This analysis was repeated, but the loss amounted to nearly the same. 

 •3244 grm. Anhydrous amygdaline. 

 27°7 Barometer at the time of experiment. 

 12°6 Thermometer at the time of experiment. 

 15-0 c c Air before commencement. 

 20 5 c c Gas and air after cooling. 



5-5 c c Azote. 



5-5 c c azote reduced to 0° thermometer and 28° barometer give 5-19 c. c. equivalent to 

 2-03 per cent., which is, according to Liebig's results, I per cent, less than the true quantity. 

 From these experiments there appears to be a constant error of about 1 per cent. This 

 error was at first supposed to arise from a diminution of the oxygen in the air of the tube 

 of combustion, destroyed in oxidising the carbon and hydrogen. With this view, carbo- 

 nate of copper was mixed with the oxide of copper, so that before the commencement of 

 the decomposition of the organic body, the heat expelled the carbonic acid of the Co„ 

 Cu 0, and drove out all the air in the tube of combustion. 

 With this modification — 



•3566 grm. Amygdaline was submitted to analysis. 

 27°6 Barometer. 

 11-4° Thermometer. 

 14 c c Air in the receiver before commencing. 

 20 c c Gas and air at the close of the experiment after cooling. 



6 c c Azote. 



6 c c azote reduced to 0° thermometer and 28° barometer give 5-65 c c, which equals 

 2-01 per cent. The loss amounts here again to 1 per cent. 

 •2456 grm. Crystallized asparagin. 

 27°4 Barometer. 

 12°7 Thermometer. 

 43 c c Air at commencement in the receiver. 

 81 c c Air and gas when finished. 



38 c c Azote. 



38 c c azote reduced 0° thermometer and 28° barometer give 35-49 c c, which equals 

 18-32 per cent. The loss here amounts to -64 per cent. 



Oxide of copper having the property of absorbing carbonic acid from the air, which is 

 expelled by the heat in the tube of combustion, and its place occupied by the mixture of 

 azote and air in the end of the experiment, it was supposed that this might be the cause of 

 the error. Bichromate of potash and dichromate of lead were then successively employed 



