1821.] On the Comparative Advantages of Oil and Coal Gas. 20& 



Somerset House, who spoke well of it, and advised me to take 

 it to the Admiralty ; but I did not pursue the matter further. ' 

 As the only question is merely as to the date of the invention', 

 and not to any imaginary superiority in principle, I need not 

 direct attention to the supposed advantage of either one or the 

 other instruments. I am, dear Sir, 



Very respectfully yours, &c. 



J.Newman. ■ 



>aii 



Article XL 



On the comparative Advantages of illuminating by Gas produced 

 from Oil and from Coal. By M. Ricardo, Esq. 



(To the Editor of the Annals of Philosophy.) 



DEAR SIR, 



The utility of employing gas for the purpose of illumination 

 is no longer a subject of doubt, but from what substance it is 

 most advantageoujsly obtained, whether by decomposing oil or 

 coal, is not yet decided by men of science. I have, therefore, 

 been induced to enter into an examination of the comparative 

 advantages of the two in order to draw the attention of those 

 who are engaged in the formation of gas light estabhshments to 

 the subject, and to enable them to arrive at a tolerably correct 

 opinion, which it would be most advisable to adopt. 



It is my intention to consider 



1 . The qualities of the two gases for producing light. 



2. The comparative facilities with which an estabhshment for 

 4;he production of either may be carried on. 



3. The capital required for such establishments. 



4. The comparative cost of the two gases. 



5. Which is most desirable in a national point of view. 



The gas produced from oil is much purer, and contains a much 

 greater illuminating power than that from coal. The quantity of 

 light produced from a given portion of oil gas is stated by an 

 eminent chemist to be equal to three times the quantity pro- 

 duced from coal gas : from the result of my own experiments, it 

 is equal to four times ; for I have found that an Argand burner 

 giving a Hght equal to six candles, six to the pound, consumed 

 one cubical foot in the hour. Mr, Accum, in his work on Ga 

 Lights, p. 276, states that an Argand burner of coal gas giving 

 a light equal to three candles, eight to the pound, consumes two 

 cubical feet per hour. Then as one foot of oil gas is equal to 

 six candles, and two feet of coal gas are required to equal three 

 candles, it follows, if the candles were even of the same size, that 

 one volume of oil gas is equal to four of coal in illuminating 



New Series, vol. i. o 



