200 Description of an Apparatus for the 



of defiant gas produced along with it, was submitted to. 

 combustion. The following table bhows the average re- 

 sults of a number of these experiments. 



TABLE IT. 



I 



No. of 1 



Weight of 



3p. grav. 



(air 1000) 



100 cubic inch. 



Kind of Coal. 



hepro-] 

 duct. 



100 cubic inches 

 (Ther.60°.Bar. 30.) 



consume 

 ox. gas 



give car. 

 acid. 



Wigan cannel. < 



1 



2 



24-28 Grs. 

 10-4 



7S3 

 S35 



234 



96 



139-7 

 49 



Wecir.ebbury coal. } 



1 

 2 



20-9 

 98 



C74 



190 

 85 



97-5 

 46 



Newcastle on i 

 Tyne. \ 



1 



19-3 



622 



190 



100 



2 



98 



316 



86 



45 



Newcastle^ Staf- \ 

 fordshire. J 



1 



2 

 3 



19-6 

 17-7 

 121 



632 



570 

 390 



195 

 165 

 100 



98 

 80 

 60 



r 



1 



20-7 



670 



190 



100 1 



Leeds. J 



2 



15.1 



487 



lost by accident. | 



X 



3 



9-8 



316 



85 



42 



\ 



1 



19-4 



627 



189 



67 



1 



2 



15 



484 



137 



65 



Black Mine, Lan- ) 



3 



11-3 



364 



ICO 



50 



cashire. \ 



4 



10 



322 



90 



47 



1 

 { 



5 



9'5 



307 



85 



45 



6 







80 



40 



f 



I 



12 



387 



117 



62 



] 



o 



9-5 



307 



90 



47 



Merthyr. J 



3 

 4 



8 

 59 



261 

 190 



75 

 60 



39 

 31 





O 



58 



187 



57 



26 



{ 



6 



5-5 



177 



50 



20 



Coal tar. 



— 



24-2 



780 



233 



150 ' 



v aoutchouc. 



— 



— 





204 



121 



An attentive examination of the results, contained in both 

 the tables, suggests the following general remarks. 



1. The olcliant gas is a very sparing product of the distil- 

 lation of pit-coal. It is found only -in the first portions^ and 

 even of these it does not compose more than 5 per cent. Its 

 quantity, however, is very much influenced by the tempera- 

 ture employed. This remark, indeed, may be extended to 

 all the aeriform products of coal ; insomuch that from equal 

 weights of the same coal it is difficult to obtain by different 

 operations conducted on a small scale, products which are 

 the same either in quantity or quality. The gas from Coal' 

 Irooke-dcle tar, and that from Caoutchouc, have a larger pro- 

 6 portion 



