Parrot Coal for yielding Gas, 229 



The gases on which the trials were made, and the results of 

 which I am now to give, were those of Edinburgh and Leith, 

 and also that of a town in the north of Scotland, to which I 

 went solely for the purpose of experimenting on this subject, 

 as I knew that a good opportunity there presented itself, owing 

 to the great distance to which the gas is sent. The illumina- 

 ting power was ascertained chiefly by the chlorine test, because 

 I found it difficult, nay in some cases impossible, to carry an ex- 

 perimental metre with me, and hence one great advantage of 

 this test. 



Trials on the Leith Gas. — 9th Deo. 1842. The gas was 

 made from Arniston coal, which was found to yield from 510 

 to 539 cubic feet per cwt., that is, taking the average, 464 

 from the 100 lb. In my trials with my own apparatus the 

 quantity amounted to 475 feet. By different trials with the 

 chlorine test, the condensation at the works, on an average, 

 amounted to 13 per cent. On the evening of the same day, 

 the gas from the same company was tried at Niddry Street, 

 Edinburgh, a distance of upwards of two miles from the ma- 

 nufactory, and the condensation there was, on an average, 12- 

 In this instance, the flow of gas in the pipes, to supply the 

 immediate neighbourhood, was not great, and I was, therefore, 

 anxious to have other trials made. I accordingly selected 

 George Street, because I knew that, from the works at Leith 

 to this situation, the pipes are laid in a direct line ; and, as the 

 flow of gas was considerable, I was convinced that that tried 

 at the works, and in the other place on the same day, would 

 be the same. — 16th Dec. At the works the condensation by 

 chlorine was, on an average, 13.7. The gas was from Arniston 

 coal, which had been in use for two days ; on the evening of 

 the same day the condensation at George Street amounted 

 to 14. 



Trials in the North of Scotland.— 26th Dec. 1842. The 

 gas was made from a mixture of two parts of Lesmahago, one 

 of Monkland, and one of Torryburn coal. The average of all 

 the trials at the manufactory, indicated by the chlorine, was 

 14.75. By the Aldcock burner, the length of flame, by one 

 inch of pressure, was 4.1 inches. The specific gravity was 590. 

 On the same day, the gas was tried at the distance of nearly 



