Dr Thomson on a ffpontaneiyus emission of Gas. 67 



Watt's rotatory double engines employed to move machine-^ 

 ry for bruising tin ores. 



HuelVor, 24. 6. 6. 12. 17.2 19.5 

 27. 5. 5. 12. 16.7 18.7 

 16.5 5. 5. 8.5 25,4 12.6 

 Average duty of rotatory enginesj 16.9 millions. 



* Watt's double engine. 



-|* The steam after passing through a high pressure escapes* 

 into a Watt's single engine. 



Art. X. — Notice respecting a spontaneous emission of In- 

 fiammahle Gas^ near Bedlay, about seven miles no7'th-east 

 from Glasgow. By Thomas Thomson, M. D., F. R. S. L. 

 and E., &c. Regius Professor of Chemistry Glasgow*. Com- 

 municated by the Autbor. 



About five weeks ago, a pretty copious emission of inflam- 

 mable gas was observed along the banks of a rivulet which 

 crosses the north road between Glasgow and Edinburgh, a little 

 to the east of the seventh milestone from Glasgow, and only a 

 few hundred yards from the house of Bedlay. The emis- 

 sion of this gas has been observed only on the south side of 

 the road. It it is said to extend for more than half a mile 

 along the banks of the rivulet. But I myself saw it only in a 

 space which might be fifty yards in length, and perhaps half 

 as much in breadth. The emission of gas was visible in a 

 good many places along the declivity to the rivulet, in the im- 

 mediate neighbourhood of a small farm-house. The farmer 

 had set the gas on fire in one place about a yard square, out 

 of which a great many small jets were issuing. It had burnt 

 without interruption during five weeks, and the soil (which 

 was clay) had assumed the appearance of pounded brick all 

 around. The flame was yellow and strong, and resembled per- 

 fectly the appearance which carhuretted hydrogen gas orjire 

 damp presents when burnt in day light. But the greatest 

 issue of gas was in the rivulet itself, distant about twenty yards 



* Redd before the Ubyal Society of' Edinburgh, January 5, 1829. 



