On some PJicenomena 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 
OLio-ht to be generally known that space is not the only thing 
oeconomized 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. If the 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 of atmospheric air, is equal 
to that evolved by 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. 
