M. J. Nicklés on a New System of Ellectro-magnets. 383 
a Tan. 4° 20’ Tan. 7° 40’ Tan. 12° 20/ 
5000 gr. 7289 gr. 10590 gr. 
“5200 7610 11000. 
5100 
._ The same electro-magnets were used in these experiments as 
in the last. I add to the tables of the results, the preceding re- 
sults, as well as those obtained in determining the weight sup- 
| If on the contrary, the two helices are of the same direction, the 
Ported by a single pole of these magnets. The currents are the 
above. 
] 
Same as ab 
- Tan. 4° 20/ 
2 pol I A singl 
ila deaee tases ere Sst, Gamma tectaes tee alee 
{ 2500 gr. 5100 gr. 1800 gr. 600 gr. 
2300 5200 
: 00 5000 5105 54500 
b 3500 5200 
5100 
Tan. 7° 40’ 
b 4800 500 4100 2500 
‘ 5000 7600 2500 
By 5800 7289 5000 2000 
{ 6000 7610 4800 
. Tan. 12° 20 
3 7000 10500 | 5000 2600 
| { 6900 10700 4850 
B 9000 10590 4800 3500 
{ 8600 11000 5000 
It follows from these facts :— 
1. That in all cases, it is an advantage to use both poles even 
When only one is under the influence of the current. 
2. That a horse-shoe magnet, furnished with a single helix, has 
More attractive power when its arms are short than when long. 
it is on these principles, that the trifurcate electro-magnet of 
Mine is constructed. 
