COAL-GAS. 



377 



and may be raised (See fig. 379). When quite empty the top rests upon 

 the ground, and when the gas enters it is raised to the top of the frame 

 which supports it. We have now our Gasometer full. When the time 

 comes to fill the pipes for lighting purposes, some of the weights are 

 removed, the Gasometer falls down slowly, and forces the gas through the 

 tubes into the main supply to be distributed. About four cubic feet of 

 gas is obtained from every pound of coal. When gas and air become 

 mixed, the mixture is very explosive. In a house where an escape of 

 gas is detected let the windows be opened at the top, and no light 

 introduced for several minutes. 



It has been calculated that one ton of good coal produces the follow- 

 ing : 



i Chaldron of coke . . . weighing 1,494 Ibs. 



12 Gallons of tar . ... 135 Ibs. 



12 Gallons of ammoniacal liquor ., loolbs. 



5,900 Cubic feet of gas .' ., 291 Ibs. 



Loss (water) .... 220 Ibs. 



Total 2,240 Ibs. 



Fig. 380. Gasome 



We can thus estimate the profits of our. gas companies at leisure. The 

 analysis of gas made by Professor Bunsen is as under, in 100 parts. 



Hydrogen . 

 Marsh gas . 

 Carbonic oxide . 

 Olefiant gas . . 

 Butyline . 

 Sulphide of hydrogen . 

 Nitrogen . . ; 

 Carbonic acid 



45*58 

 34-90 

 6-64 

 4-08 

 2-38 

 0-29 

 2-46 

 3-67 



lOO'OO 



Gas, therefore, is very injurious, for it rapidly vitiates the atmosphere 



