532 
M‘GAULEY’S EXPERIMENTS^. 
ed, and the arranf^ements examined be- 
fore each of the following; experiments, 
and the materials of the charge were, as 
far as possible, not merely similar, but 
identically the same. 
First Series. The Helix. 
No. 1. — A horse-shoe soft iron bar 
13^ inches across, to the extreme edges 
of the poles, interior, 7f exterinn 
length. The diameter of the bar 2| 
inches, its weight 29| lb. The keeper 
used was 13|- inches long, 21 wide, f- 
thick; its weight, with ring, /fib. This 
keeper was used in all experiments with 
magnets of the same size. This, like 
all the other magnets, was well coated 
with sealing-wax varnish; it was coiled 
with I69O feet of No. 13 copper wire, in 
10 equal coils. The battery was one 
foot square^ double cell, charged with 
1 in 50 sulphuric acid, 1 in 100 nitric 
acid, and water. 
Keeper distant from poles 3-10 inch, 
it lifted 4| lb. 3-20 9i 
Magnet No. 1, of 5th Series, connec- 
ted wdh the battery, at the same time, 
lifted in contact 9|lb. 
He removed one of the coils, used the 
same battery, and a similar charge, at 
the distance, 
3-l0 inch, it lifted 7i lb. 
3-20 37 
i. . 26i 
The one of last year, though perfectly 
successful, required the agency of mer- 
cury, which, for many reasons, is ob- 
jectionable ; it becomes oxidated, then 
contact is imperfect, and the level in 
the cups, which is of the last import- 
ance, is destroyed : it is liable to a 
thousand accidents, not speak of its 
destroying the wires of the apparatus 
itself.* 
The spark, on breaking contact, was 
very brilliant. 
Same magnet, battery, and similar 
charge, but the poles of the battery 
and the magnet thicker wire, it lifted 
at. 3-10.. ]4i lb. 
3-20..^ 24 
i . . 32i 
Same magnet, battery, and charge, 
but thicker zinc plates, it lifted 
at. i . . 32i lb. 
Same magnet, &c. thin- 
ner plate. i . 60 
Same magnet battery, and charge, 
one coil of the same wire, 150 feet in 
* See plate iv. fig 1. 
length,, i perceptible in 
contact 12i ft). 
Same magnet, battery, charge, &c., 
2 separate coils, each 150 
feet 1-16.. 5f ft). 
Same magnet, battery, charge, and 
coils, the two coils formed into one of 
300 feet, at same distance f lb. 
Same magnet, battery, and charge, 
3 coils, making together 
450 feet f . . . 2| lb. 
i ....3i 
i ....4f 
1-16.. 9i 
The wire was coiled in larger quanti- 
ty near the poles. 
Same magnet, battery, and charge 4 
coils, 600 feet, it lifted at i 2| ft). 
i .... 3^ 
i ...3f 
1-16.. 12i 
Wire coiled equally over the magnet. 
Same magnet, battery, and charge, 5 
coils, 750 feet, at 4 perceptible. 
i ....3i lb. 
i ,...2h 
i ...,4i 
1-16. .12i 
Wire rather more on one pole. 
Same magnet, battery, and charge, 6 
coils, 900 feet, at | 3| lb. 
I ....3 
i .. 3 
i . . . . 7i 
1-16. i8i 
Same magnet, battery, and charge, 7 
coils, 1050 feet, at ^ "I percepti- 
1/ ble 
i ....2i lb. 
i ..5f 
1-16. 19i 
Wire coiled evenly. Battery dimi- 
nished in energy almost immediately. 
Same magnet, battery, and charge, 
8 coils, 1200 feet, at. . . . i . . . . 7| tb. 
^ . . . . 04 
1-16 30A 
Wire coiled more on the poles. When 
it lifted at 1-16 30^ tb, its energy was 
so far diminished as to be at i inch 
scarcely perceptible. 
Same magnet, battery, and charge, 
9 coils, 1350 feet, at. .. . ^ , .5^ lb. 
I . . . . 6i 
i ....91 
i .. ..8i 
1-16 .2li 
