and other Siibstances hy Electricity. 21 



has left us entirely in the dark with respect to the lew that is 

 necessary to be observed in varying the experiment. For al- 

 though the dimensions of his jar and tube are given, no men- 

 tion whatever is made, why it is necessary to observe those 

 dimensions, or why other jars and tubes of various other di- 

 mensions may not answer as well. Indeed, so little does Mr. 

 W.'s hypothesis concur with the conclusions deduced from 

 my experiments, that he supposes the water derives its retard- 

 ing property solely from its confinement in tubes. For it is 

 stated in Mr. W.'s paper, " If the tube be filled with a3ther 

 or alcohol, and placed in the circuit, the powder will be in- 

 flamed. If it be filled with sulphuric acid, which is a better con- 

 ductor, the powder will be scattered and not inflamed : but 

 the dispersion will not be so great as when metals only form 

 the circuit." 



" The same effect will be produced by transmitting the 

 charge through the animal oeconomy, or through water not 

 inclosed in tubes, in which case the water does not appear to 

 oppose a sufficient resistance to the passage of the fluid." 



It is evident from this statement of Mr. Woodward's, that 

 he never varied the experiment by employing tubes of various 

 diameters; his experiments being with different fluids in the 

 same tube. Had Mr. W. taken into consideration the ne- 

 cessity of varying the diameter of the tube with the nature of 

 the charge, I suspect he would have found little difficulty in 

 igniting gunpowder by transmitting the electric fluid through 

 sulphuric acid, it being necessary to observe nothing more 

 than to augment the charge, or reduce the diameter of the 

 tube. 



That the retarding property of water does not depend on 

 its confinement, is evident from the success of my experiments 

 with a moistened thread exposed to the open air. Indeed, so 

 certain it is, that confinement does not impart to water this 

 property, that gunpowder may be ignited in the electrical cir- 

 cuit, by transmitting the fluid through a sufficiently narrow 

 streak of water, drawn on the surface of a piece of flat glass. 



I should, however, be extremely sorry to detract any thing 

 from the merits of any man ; and although Mr. Woodward's 

 explanation of igniting gunpowder by the electric fluid, when 

 transmitted through water, does not exactly agree with the 

 principles on which I suppose the action to depend ; I never- 

 theless should be wanting in candour, were I not to express 

 my sentiments on the highly interesting nature of his experi- 

 ments : and I feel a pleasure in acknowledging that Mr. W. 

 has preceded me in some that are detailed in my paper (al- 

 though I did not know it at the time) ; viz. those wlierein gun- 

 powder 



