208 Mr. Murray on the [Sept* 



to the vehicle. I was, however, determined to do what I could 

 to revisit a phenomenon which had not fully satisfied my curio- 

 sity, and had frequently been the object of my thoughts. With 

 this anxiety, I sought out a guide, who, to my satisfaction, 

 told me that it was practicable. We accordingly set off three 

 to four feet deep in snow, while the vetturino moved slowly on. 

 My guide and 1 were within half a mile of the wished-for spot, 

 when he, being a few yards before me, suddenly disappeared 

 among the snow, in a ravine ; and I then thought it high time 

 to sound a retreat. Defeated in my attempt, I have only to add, 

 that my guide had told me that the gas was about four feet high 

 at this period, that the flame was very greatly increased by 

 throwing a quantity of snow upon it, and that on the approach of 

 wet weather, or during rain, it was always highly magnified. 

 Does not this singular resuit find a proper analogy in the so 

 called " American Tar and Water Burner," and do they not 

 mutually illustrate each other? I certainly think so; and I 

 confess that to me it is otherwise inexplicable. It may be 

 doubted whether the Gas Light Companies can avail themselves 

 of this discovery in the propulsion of steam through the pipes 

 along with the gas. 



Mr. Lawe, in vol. liii. of the Philosophical Magazine, p. 266, 

 notices the etherial odour which evolves on slowly burning a 

 very depressed flame of coal gas. Every chemist has remarked 

 a similar thing in his experiments on supercarburetted hydrogen 

 in the laboratory ; and when a mixture of one part of alcohol and 

 three parts of sulphuric acid are heated over an Argand's lamp 

 in a glass retort, the inflammable vapour which comes first over 

 and inflames with a diluted blue flame is particularly distinguished 

 for its etherial smell. There can be no doubt whatever but that 

 sulphuric ether might be obtained in quantity by the slow com- 

 bustion of coal gas, and this may become a source of wealth to 

 the proprietors of gas light shares. The etherial smell which 

 accompanies the gas of the Apennines is strongly presumptive in 

 favour of the opinion that it proceeds from a bed of coal beneath. 

 The gas which bubbles from the Acqua Briga is an additional 

 evidence, and such wells are found in the vicinity of coal mines 

 as at Wigan, in Lancashire. 



Thus supercarburetted hydrogen slowly consumed by flame, 

 and in such circumstances as to increase the surface exposed to 

 the ambient atmosphere and the supply of absorbed oxygen, 

 produces an etherial vapour; and this product again subjected 

 to the aphlogistic effect of silver on platinum by a still slower 

 combustion, evolves that which has been absurdly termed lampic 

 acid. 



The application of different intensities of temperature is parti- 

 cularly striking and curious in the obtainment of gas from coal. 

 If the heat applied to the retort be a low red heat, the light of the 

 gas is feeble in its illuminating powers ; and when it is exalted to 



