144 Galvano-magnetism. 
effect is produced. I have also been constructing a new galvanic 
battery in two parts, each containing five hundred pairs of six inch 
plates; the effect I have as yet tried only with water and about a 
pound of salt; with this mixture, it fuses sul instantly, and gave 
the globules, which you consider, fused carbon. 
In constructing the magnetic apparatus, there is considerable econ- 
omy in using sealing wax instead of silk. I stretch my wires across the 
room, and with a spirit lamp heat each wire, following on with a stick 
of wax, which melts and covers the wire very equally ; but I think 
the solution in alcohol preferable, as being less brittle and more 
readily applied. 
Since the above was written, Dr. W. informs me that one hun- 
dred and twelve pounds were held suspended, during twenty one 
hours after the coil had been removed from the acid, and the plates 
had become perfectly dry —Ed. 
_ Prof. Hare, in a letter dated Feb. 24, writes—I have just made 
an apparatus, upon a small scale, in imitation of that of Prof. Henry 
of Albany, and it is quite successful. I used four coils of bell wire, 
of about fifteen feet each, wound first to the right, and then back 
over the coil first made, so as to bring the commencing and termina- 
ting wires to the same ends of the coils. All the commencing wires 
were soldered to one lead rod, and all the terminating wires to anoth- 
er, and these rods were severally made to communicate with the poles 
of a calorimotor, of about a square foot of zinc surface. I used n0 
wrapping, but merely shell lac varnish, applied in winding, and pa 
per between the coils. The magnet consists of an iron bar of three 
eighths of an inch diameter. It easily holds a fifty six pound weight 
~~vand Would bear, I believe, a twenty eight in addition. 
In another letter dated March 4th, Dr. Hare, in answer to enqui- 
ries which had been proposed to him as to his mode of construction, 
_ writes—that the wire was varnished by mixture of a thick solution 
of shell lac, in alcohol, and vermilion, the varnish being applied 10 the 
winding of the coils. This process was performed by a mandrill 
turned by a lathe, by means of a dog and centre points. ‘The marr 
drill, a round iron bar of the same size and shape as the magnet 
was wrapped in a coil of paper so as to thicken it. The coils were 
wound upon this for about two inches, one forward and one backs 
and between the first and second layer paper was interposed. 
