406 Mr. Dewey on Gas Illumi?iation, [Dec 



Brick-lane and Dorset-street stations, in London, uses similar 

 ones, and finds them answer better than the round ones. The 

 former are both theoretically and practically the best. The coal is 

 more equally and more speedily carbonized. The fire comes more 

 readily m contact with every part. The thinner the coal is in 

 the retorts the better. Perhaps you will say I have seen many 

 more gas works than I have mentioned : true, and there are 

 many who understand them better than I do. When I get 

 home, and find I know enough to construct a work which shall 

 answer our purposes, and the people like the gas, and use it, and 

 pay as fairly for it, then I may send you another article, but not 

 so long^as this. 



At Paris, I examined their coal gas works, and one oil gas 

 work. Here I met with the most frank and gratifying treat- 

 ment from Messrs. Say, Thenard, and Darcier, who interested 

 themselves to procure me admission to the gas works ; the mana- 

 gers of which showed me every thing, and treated me equally 

 well. Gas works in Paris will long have to contend against the 

 best lamps and purest oil I have seen. Light is not used nearly 

 so late in Paris, except in the coffee-houses, as in England, 

 which is a great drawback on this kind of industry. The oil gas 

 here is obtained from oleaginous seeds, principally from the 

 colza and hempseed ; the quantity great, but the illuminating 

 power not quite half (as nearly as I could determine by a few 

 experiments), that from fish oil. It is not so offensive as coal 

 or oil gas. I think this work will be profitable. One coal gas 

 work may be profitable too. I understand that the largest is to 

 be removed beyond the walls of the city. They have a gaso- 

 meter which may contain 256,000 feet of gas, and a removal 

 will destroy the concern. I beheve many people are taught that 

 such a large gasometer is dangerous. I do not think there is 

 much fear of a gasometer's exploding. Some trifling explosions 

 may occur in confined places, but they will never injure any 

 body. They are not half so dangerous as most mechanical 

 employments, or a windmill, which no one is afraid of. 



1 have not volunteered these opinions, or stated facts to serve 

 any separate interest. Both systems can be successfully prose- 

 cuted, and that to be preferred must depend on so many local and 

 contingent circumstances, that every one must judge for himself. 

 My business was to acquire correct information on this inte- 

 resting subject to enable me to give my employers the means of 

 judging which system would best answer our particular situa- 

 tion ; and as they had given me power to act for them to a cer- 

 tain extent, I have deciaed as above stated. I have been much 

 longer absent than they expected ; and I fear am not so well 

 informed as they could wish. 



I am happy to say that the statements made to me by Messrs. 

 Taylor and Martineau, respecting the consumption and illumi- 

 nating power of oil gas, have been verified by the experiments 

 they enabled me to make. Were gas works now to be erected 



