1821 .J of illuminating by Gas from Oil and from CoaL 211^ 



occurrence, and many other disasters both in the use of oil 

 and candles, from all of which gas is exempted ; and when the 

 prejudice arising from the use of coal gas is once removed, and 

 the greater advantages of oil gas generally know^n, there is no 

 doubt its great convenience, superior brilliancy, and cheapness, 

 will cause it to supersede all other modes of lighting, and before 

 long, its universal introduction into dwelling houses may be con 

 fidently reUed upon. 



The second point for consideration is the comparative facility 

 with which a coal or oil gas establishment may be carried on* 

 The process for producing gas from oil is very simple. The appa- 

 ratus is easily managed, and consists of an iron retort heated 

 over a fire : a very few days* experience will teach a common 

 working man how to regulate the heat. This retort is connected 

 by a tube with the oil cistern, from which a small drop of oil 

 passes into it. The quantity is regulated by a graduated cock; 

 there it is decomposed and converted into gas. This passes 

 through another tube at the other extremity of the retort into a 

 condensing vessel, where, by a simple contrivance, the oil that is 

 only volatilized returns back into the oil cistern ; the gas is then 

 conveyed into a wash vessel, where it passes through water to 

 deposit any oil, or other condensible vapour, that may have come 

 over with it, and from thence it is conducted into the gasometer 

 for use. 



Coal gas is produced by putting a certain quantity of coal in 

 an iron retort placed over a fire. The coal is decomposed ; the 

 gas passes over into a large vessel, where it deposits its tar and 

 ammoniacal liquor ; it is then conveyed through a mixture of 

 lime and water to deprive it of the sulphuretted hydrojen which 

 is mixed with it, a most troublesome and offensive operation: 

 after this, it is passed through water, where it is more effectually 

 washed, and from thence it is transmitted into the gasometer. 

 These are the processes required for producing the oil and coal 

 gas ; but we shall better understand the trouble attendant on the 

 latter by a comparative view of two establishments for a thousand 

 lights each, one for oil, and the other for coal gas, each light 

 consuming annually, upon an average, 2000 cube feet of oil gas,. 

 and 7000 cube feet of coal gas. The whole annual consumption 

 of the one would be 2,000,000, of the other 7,000,000 cube feet. 

 The quantity of hght required in winter is of course much greater 

 than in summer, and either establishment must be made upon a 

 scale to meet the demand that may be necessary on the shortest 

 days. The fortnight before and after Christmas, or about that 

 "time, may be taken as the month of the greatest consumption*; 

 and we may assume that durino; this month, nearly one-fourth of 

 the whole quantity would bo required. 1 may mistake in this 

 estimate, but it can be of no consequence, as it will equally apply 

 to both establishments. The average quantity of oil gas required 

 would be, during that time, somewhat above 16,000 cube feet 



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