1 44 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 substances 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 afte?- 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 no 

 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, 

 and would bear, I believe, a twenty eight in addition. 



In another letter dated March 4th, Dr. Hare, in answer to enqui- 

 jfies 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 vermihon, the varnish being applied in 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 man- 

 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 back, 

 and between the first and second layer paper was interposed. 



