jol Experiments and Ohfervalhus made ivitb the View of afeerl.iining 



It fccmcd as if the elciflricnl difcharge had kindled the oxygen and hydrogen gaz of the de> 

 compounded gaz, by flying from the bottom of the wire to the brafs funnel, fo that the fire 

 returned into the tube where it paflcd through the gaz. Or the combuftion might be oc- 

 eafioncd by a chain of bubbles reaching from the brafs didi to the furface of the water in 

 the tube, which was fet on fire in its afcent, and thus produced combuftion of the whole 

 of the gaz of decompounded water. 



That this phenomenon was from the combudlon here fuppofed, was in fome degree 

 proved, by finding that the mixture of liydrogen gaz and atmofplierical air, under the fame 

 circum fiances, was kindled in the fame manner. 



Experiment II. With a double plate cleiflrical machine, 24 inches in diameter, and a 

 fimilar apparatus to that in the laft experiment, 14,600 difcharges produced at lead one- 

 third of a Cubical inch of gaz. While I was meafuring with a pair of compalTes the quan- 

 tity of gaz produced, the points of them being in contacl with the part of the tube occu- 

 pied by gaz, I was again furprifed, on the palTmg of a difcharge, by an illumination of the 

 whole tube, and the rufliing up witli confideruble commotion of water, to occupy about two- 

 thirds of the fpace filled by gaz. 



The rcfiduary air was found, as in the former experiment, to be rather worfc than at- 

 mofpherical air. 



It was concluded that the points of the compaffes had attra£led eledrical fire from the 

 wire to the fides of the glafs, and thereby kindled the hydrogen and oxygen gaz of decom- 

 pounded water. But to determine this quellion, I introduced into the fame tube a mixture 

 of one meafure of oxygen and two meafures of hydrogen gaz, to occupy nearly the fame 

 fpace in the tube as the gaz had occupied ; then pafling an ele£trical difcharge through it, 

 no combuftion was excited ; but on pafiing a difcharge, while the compares were in contadl 

 with the tube, as juft mentioned, an illumination and violent commotion were produced, 

 with the ruQiing up of water, to leave only i-8th of the gaz as a refidue. On repeating 

 this experiment with two meafures of atmofpherical air, and one of hydrogen gaz, combuftion 

 could not be excited -, nor with one meafure of atmofpherical air, and two of hydrogen ; 

 but on adding to this laft mixture one meafure of oxygen gaz, the eleflrical difcharge 

 produced the phenomena of combuftion juft mentioned, with the ruftiing up of water, to 

 occupy about two-thirds of the fpace which was occupied by the gazes. 



Experiment III. Having pafled I 2,000 difcharges through water, with the apparatus of 

 the preceding experiment, and thereby obtained only one-fifth of a cubical inch of gaz ; 

 and having obferved that the quantity of gaz was not greater than it was when only 8000 

 difcharges had been pafled, and yet bubbles had been feen to be produced on each difcharge, 

 as copioufly, or more fo, by the laft three or 4C00 difcharges, as before ; I began to fufpeft 

 that part of the gaz liad been deftroyed during the proccfs, or had-been abforbed. While 

 I was confidering how to account for this difappearance of gaz, and was at the fame time 

 looking at the tube through which the difcharges were paffing, I obferved one of them to 

 be attended with a diminution, inftantly, of about one-fiftli of the gaz produced, and with 

 a (light explofion. I was now fure, from this phenomenon, and from the unequal aug- 

 mentation of the bulk of the gaz at given times during the procefs, that combuftion had 

 been excited fevcral times before, not only in the prcfent experiment, but perhaps in the 

 former ones, without obferving it. I conceived that a gradual combuftion alfo very pro- 

 bably 



