from gas for various purposes in the Arts. 105 



sufficiently heated. In examining the nature of the flame 

 thus produced, I found that it differed in the most essential 

 manner from all other flames. The flame of a candle, of gas, 

 and of spirit of wine is entirely a superficial film of a conical 

 form, there being no oxygen in the interior of the cone 

 to promote combustion, as has been proved by Mr Sym 

 and Mr Davies. Hence these hollow flames produce com- 

 paratively very little heat. The flame, on the contrary, 

 produced above the wire gauze is a solid mass, similar to that 

 of the oxihydrogen blowpipe, and therefore it produces a very 

 intense heat. The term flame, indeed, cannot with any pro- 

 priety be applied to it. It is in reality a succession of explo- 

 sions of the explosive mixture formed by the gas and atmo- 

 spheric air. Having thus ascertained the cause of the intense 

 heat, generated by this method of using gas, I conceived that 

 it might be advantageously applied to various purposes in the 

 arts, particularly as no smoke is generated during the combus- 

 tion. At this period of my inquiry, I learned that Dr An- 

 drew Duncan Junior had, a considerable time ago, been in 

 the habit of burning gas above wire gauze in his pharmaceuti- 

 cal experiments, chiefly with the view of diffusing the heat 

 over a greater surface ; and I have since found, that an inge- 

 nious American gentleman, Mr Samuel Morey, made numerous 

 experiments for obtaining heat by burning the vapours of dif- 

 ferent substances through wire gauze. The following inte- 

 resting experiment deserves to be quoted.* " If the vapour 

 of spirits of turpentine be made to pass through a tube covered 

 at the upper end with fine wire gauze, it burns with much 

 smoke : If a quantity of atmospheric air be allowed to mix with 

 it, the smoke arises, but the flame continues white. If more 

 still be added, the flame lessens and becomes partly blue. By 

 adding: still more and more it will burn with a very small flame, 

 entirely blue, and with a singular musical sound. If still more 

 be added, the flame and every ray of light ceases, but that 

 the combustion still continues is certain, from the explosive 

 detonajting noise or report continuing to be distinctly heard." 

 The object which I had principally in view was to produce 



* Letter to Professor Silliman, May 4, 1819. 



k^ 



