"GS Ko/ices respecting New Books. 



of carbiiretted hvdrogcii, or hvdrocaibonate gas, the weight 

 of which is to common air as 4S0 to 1000. 100 mcasurts 

 of this gas require for their saturation 60 measures of oxy- 

 gen gas. On the vapour of water being brought into con- 

 tact with charcoal, this species of gas is formed, together 

 with carbonic acid. 



" The gas obtained by the destructive distillation of pit 

 coal has been successfully applied to the purpose of aflord- 

 ing light by Mr. Murdoch in 1 792, when he ascertained that 

 it could be employed as a substitute for lamps and candles. 

 It has been since used for similar purposes in France, fornir 

 ing what has been termed the t/iermo lamp. Mr. Henry, 

 pursuing Mr. Mujrdoch's experiments, found that hydrogen 

 gas, carburetted hvdrogen gas, obtained by passing water 

 over ignited charcoal, and tlie carbonic oxide, burnt with a 

 very triflinii; production of light ; and was induced to in- 

 quire into the cause of the difierence between these gases 

 and that derived from pit coal. The latter gas, when re- 

 cently prepared, evidently contains inflammable matter sus- 

 pended in it, which then increases its illuminatinii; property; 

 but this is subsequently deposited : still, however, ihe aas 

 possesses, the property of burning with a bvio;ht compact 

 flame. The inquiries of Mr. Henry led him to the conclu- 

 sion, that the light is in proportion to the quantity of com- 

 bustible matter, and consequently to the quantity.of oxygen 

 consumed in the combustloii. He therefore went tlirough 

 a scries of experiments, by which he ascertained the quanr 

 tity of oxygen gas required to saturate 100 measures of each 

 gas, as -well as the quantity of carbonic acid gas produced, 

 as is shown in the followinjr table : 



Measures of 



Carboiiic Acid 



produced. 



Kind of Gas. 



liVleasKres of Oxygcii 

 GnS rc-quircd to satu- 

 ra;e 100 M-casurfs. 



Pure hydrogen - _ - 



jGas from moist charcoal - 



wood-(oakj - - 



dried p'jat - - 



coal, or canncl - 



latnp oil 



wa.x - - - - 



tPurc defiant I'.^s - - _ 



50 to 51 



60 



54 



68 

 170 

 190 

 220 

 984 



35 

 33 

 43 

 100 

 1'24 

 137 

 179 



" j\'oWj 



