M’GAULEY'S EXPERIMENTS. 
533 
Same battery, magnet, and helices, 
charge 300 drachms water, lOg sulphu- 
ric, 5^ nitric acid. 
1-I6.l7ilb. 
The wire was coiled evenly, and filled 
the inside curve of the magnet. 
SECOND SERIES. 
Same magnet and battery, charge 400 
drachms water, 8 sulphuric, 4 nitric 
acid ; all the coils remaining on those 
nearest to the iron connected with the 
battery, lifted, at 1-16 inch, the follow- 
ing quantities. 
Average of a great number of Experi- 
ments : — 
9 coils.1350 feet.l9|lbs.' 
8.. 
.. 1200.. 
,. 26| 
7.. 
. 1050.. 
. .22f 
6.. 
. . 900. . 
.. 18f 
5. 
.. 750.. 
.. 13§ 
4.. 
. . 600. . 
..lU 
3. 
.. 450.. 
.. 7i 
2.. 
.. 300.. 
. . 
1.. 
.. 150.. 
.. 2i 
The ninth 
helix on this 
occasion oc- 
cupied nearly 
^the same place 
"as the tenth 
on the former, 
and like it, was 
injurious to the 
effect. 
THIRD SERIES. 
Same magnet, battery, charge and 
helices, 
2 helices arranged so as to form but 
one, lifted at 1-16 inch 5| lb. 
3 helices forming one 4^ 
4 7i 
5 
6 0 
1 4f 
FOURTH SERIES. 
Magnet No. 1, horse-shoe bar, 9l 
exterior length, from extremity of 
poles to highest joint of exterior* 
curve, diameter of bar 1-58 inches, 
dises surmounting the poles 4 inches 
diameter, 1-8 thick. Coiled with 500 
feet of No. 15 iron wire, in 5 equal he- 
lices. Keeper 9i inches long, 4 3-16 
wide, f thick, weight, with ring, 91 lb., 
battery 1 foot square, double cell, 
charge 400 drachms water, 8 sulphuric, 
4 nitric acid. Flannel casings of the 
zinc plates new. 
At 1- J 6 of an inch this magnetlifted 61bs. 
Magnet No. 2, same size, &c. coiled 
with 500 feet of No. 13 copper wire, in 
5 equal helices, same arrangement, bat- 
tery, and charge. 
This magnet lifted at i inch 4 lb. 
1 - 16 .... 71 
Magnet No. 8, same size, and coilled 
with 500 feet of No. 12 iron wire, same 
arrangement, battsry charge, &:c. 
This magnetlifted at i . . . . 1^ lb. 
1-16.... 4 
When the keeper was in contact 
with this magnet, reversion of the poles 
was not effected. The reversing appa- 
ratus used was that exhibited to the 
Section last* year. 
Magnet No. 4, same size, &c. except 
that the ground dises at the poles were 
replaced by pins, for the purpose of re- 
taining the wire. Coiled with 500 feet 
No. 12 iron wire, in 5 equal helices, 
same battery, charge, &., hardly any 
magnetic effect, although Magnet No. 
2 of this series, when connected at the 
same time with the battery, was pow- 
erfully excited fig. 
Magnet No. 1, same battery &c. Flan- 
nel cases of zinc plates had now been 
used several times, 
at 1-16 inch lifted. . 2| lb. 
Magnet No. 2, again at i inch . . . . 5^ 
1-16 l4i 
I had frequently remarked an electro- 
magnet to improve by use. 
FIFTH SERIES. 
Magnet No. 1, soft iron square horse- 
shoe bar, interior length 5.15-16, exte- 
rior 7f inches, f inch square, coiled with 
one helix of 90 feet No. 13 copper wire. 
Magnet No. 2, cast iron^ same size, si- 
milar helix. 
Magnet No. 3, wrought iron, same 
length, but round bar, f diameter ; coil- 
ed with a similar helix in two lengths, 
each coiled over the entire bar. 
Magnet No. 4, same size, &c., coiled 
with 60 feet of same wire in two helices, 
one helix on each half of the bar, the 
coils increasing in number from the 
centre to the poles; battery 1 foot 
square, double cell, charge 300 drachms 
water, 6 sulphuric, 3 muriatic acid. 
This charge remained unchanged 
throughout this series. Keeper No. 1, 
5| inches long, i wide, I thick, weight 
12§oz. Keeper No. 2, same length, 
double thickness, weight 18t oz. ; there 
was, of course, but one ring to the 
larger as to the smaller keeper, which 
See plate iv fig 2; 
• See plate iv. fig 3. 
