Mr. Richardson on the Composition of Coal. 405 



instead of oxide of copper, but it was found impossible to avoid the formation of deutoxide 

 of azote with these substances, in such quantities as to be reduced by the copper. Oxide 

 of lead was also used, but the combustion was quite imperfect and the quantity of ammo- 

 nia formed very great. Oxide of copper, strongly heated, was at last employed, but the 

 error remained the same. 



The method remains thus at the present time, but we hope, by further investigation, to 

 discover the cause of the error. The error being thus confined to 1 per cent, two analysis 

 of coal were made, in order to obtain some idea respecting the amount of the azote. These 

 coals will be more minutely described afterwards. 



I. '283 grm. coal from the neighbourhood of Edinburgh. 



27°7 barometer. 



13°4 thermometer. 



11-8 c. c. air in the receiver. 



12-7 c. c. gas and air, after the experiment. 



•9 c. c. azote. 



•9 c. c. azote reduced to 0° thermometer, and 28° barometer, give 

 •84 c. c. which equals -38 per cent. 

 II. 300 grm. coal from Garesfield, near Newcastle upon Tyne, afforded no gas, but there 

 appeared to be a dimunicion of -3 c. c. 



From the above experiments, it clearly appears that the coal cannot contain more than 2 

 per cent, of azote, but with the present means of analysis at our disposal, it is impossible to 

 determine the true amount. 



ANALYSIS OF THE COALS, &c. 



The arrangement of the various coals, proposed by Dr. Thomson, has been for the pre- 

 sent adopted in the following account. Two specimens of each of these varieties from dif- 

 ferent localities have been analysed. There are four varieties, viz., Splint, Cannel, Cherry, 

 and Caking. 



I. VARIETY — SPLINT COAL. 



1. Specimen from Wijlam Banks. 



This coal is not at present worked ; it is a thin bed very low down in the Newcastle 

 coal series, and appears in this spot by the River Tyne cutting through it. Colour, black ; 

 lustre glimmering ; difficultly frangible ; principal fracture imperfect conchoidal ; cross 

 fracture uneven and splintery; specific gravity, 1-302. 

 The ashes determined, as already described, were — 



I. 1-234 grm. coal left as residue, -1715 grm. ashes. 



II. -0864 grm. ditto ditto, -0122 grm. ditto. 



1-3204 -1837 



Which amounts to 13-912 per cent. 



VOL. II. 4 C 



