on the Construction of a Voltaic Apparatus. 37 
The great similarity of the appearance of the electric light of 
this battery in vacuo, and that of the common machine, might 
also be urged as an additional proof of the identity of their 
nature. 
The effect of this large combination on imperfect conduc- 
tors, was, as may be supposed, very great ; but of the same 
platina wire, of which the four-feet plates fused eighteen 
inches, this battery melted but half an inch, though, had the 
effect been in the ratio of their surfaces, it should have fused 
nearly fourteen inches. 
The absolute effect of a Voltaic apparatus, therefore, 
seems to be in the compound ratio of the number, and size of 
the plates : the intensity of the electricity being as the former, 
the quantity given out as the latter ; consequently regard 
must be had, in its construction, to the purposes for which it 
is designed. For experiments on perfect conductors, very 
large plates are to be preferred, a small number of which will 
probably be sufficient ; but where the resistance of imperfect 
conductors is to be overcome, the combination must be great, 
but the size of the plates may be small ; but if quantity and 
intensity be both required, then a large number of large plates 
will be necessary. For general purposes, four inches square 
will be found to be the most convenient size. 
Of the two methods usually employed, that of having the 
copper and zinc plates joined together only in one point, and 
moveable, is much better than the old plan of soldering them 
together, through the whole surface, and cementing them 
into the troughs : as, by the new construction, the apparatus 
can be more easily cleaned and repaired, and a double quan- 
tity of surface is obtained. For the partitions in the troughs, 
