374 LETTERS ON NATURAL MAGIC. 



and only a few fyundred yards from the house of Bedlay. 

 The gas is said to issue for more than half a mile along 

 the banks of the rivulet. Dr. Thomson, who has analysed 

 the gas, saw it issuing only within a space about fifty 

 yards in length, and about half as much in breadth. 

 " The emission of gas was visible in a good many places 

 along the declivity to the rivulet in the immediate 

 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 

 perfectly the appearance which carburetted hydrogen gas or 

 fire damp presents when burnt in daylight. But the 

 greatest issue of gas was in the rivulet itself, distant 

 about twenty yards from the place where the gas was 

 burning. The rivulet when I visited the place was 

 swollen and muddy, so as to prevent its bottom from being 

 seen. But the gas issued up through it in one place with 

 great violence, as if it had been in a state of compression 

 under the surface of the earth ; and the thickness of the 

 jet could not be less than two or three inches in diameter. 

 We set the gas on fire as it issued through the water. 

 It burnt for some time with a good deal of splendour ; 

 but as the rivulet was swollen and rushing along with 

 great impetuosity, the regularity of the issue was neces- 

 sarily disturbed, and the gas was extinguished." Dr. 

 Thomson found this gas to consist of two volumes of 

 hydrogen gas and one volume of vapour of carbon ; and 

 as its specific gravity was 0*555, and as it issues in great 

 abundance, he remarks that it might be used for filling 

 air-balloons. "Were we assured," he adds, "that it 

 would continue to issue in as great abundance as at pre- 



