On some Phaenomena of the Voltaic disruptive Discharge. 479 



obtained was 0'4 of an inch long. I am anxious to avoid the 

 bad taste of eulogizing my own productions, but I think it 

 ought to be generally known that space is not the only thing 

 osconomized in this combination. Professor Jacobi, who has 

 recently written a paper on my battery, and who has wrought 

 on a large scale, states that he has readily fused iridium, &c. 

 &c. after it has been at work for a whole day. An obvious 

 point in the practical oeconomy of the voltaic battery is, that 

 the more intense the power of a combination the greater the 

 oeconomy, e. g. if one combination can effect with a series of 

 two pair, what another can only effect by a series of 20, the 

 equivalents consumed are as 1 to 10 in favour of the former. 



But to return : experiments made with this battery esta- 

 blished the following points : 



1st. If zinc, mercury, or any oxidable metal constitute the 

 positive electrode, and platina the negative one, in atmo- 

 spheric air, while the disruptive discharge is taken between 

 them, a voltameter inclosed in the circuit yields considerably 

 more gas than with the reverse arrangement. 



2nd. In an oxidating medium the brilliancy and length of 

 the arc are (with some conditions to be presently noticed) 

 directly as the oxidability of the metals between which the 

 discharge is taken. N.B. Platina is to be regarded as slightly 

 oxidable when influenced by the voltaic discharge ; if this be 

 taken for some time between platina points in oxygen, the 

 volume of the gas is diminished. 



3rd, In an oxidating medium the heat and consumption of 

 metal is, as observed by Mr. Gassiot, incomparably greater 

 at the anode than at the cathode. 



4th. Ifthe disruptive discharge be taken in dry hydrogen, 

 in azote, or in a vacuum *, no difference is observable between 

 the light and heat, whether the metals be oxidable or inoxid- 

 able, or whether the oxidable metal constitute the positive 

 or negative electrode. 



5th. The volume of oxygen absorbed by the disruptive 

 discharge taken between a positive electrode of zinc and a 

 negative one of platina in a vessel ©f atmospheric air, is equal 

 to that evolved b}'^ a voltameter included in the same circuit. 



These experiments present a remarkable analogy between 

 the electrolytic and disruptive discharges. There are, how- 

 ever, two important elements, alluded to in art. 2. which obtain 

 in the latter, and which have little or no influence on the 

 former ; these are the volatility and the state of aggregation or 

 tenacity of the metal or conducting body. This is remarkably 

 shown in the case of iron. Iron in air or oxygen gives a most 



* I have not been able to experiment in a Torricellian vacuum ; in a 

 well-exhausted receiver, the difference, if any, was very slight. 



