TRANSACTIONS OF THE SECTIONS. 



25 



of attaching it to the machinery, so as to be worked by it, is over- 

 come. He reserved for a future occasion its description. 



The following experiments he had tried with great care, securino- 

 as far as possible, by cleaning the battery, renewing the charge! 

 &c., a perfect identity of circumstances, without which a fair com- 

 parison could not be made. 



The Helix. 

 Magnet, No. 1.— Horse-shoe soft iron bar, 13A inches across 

 the poles ; 5^ interior, 7| exterior length ; diameter of the bar 

 ^ mches ; keeper 131 inches long, 2^ and f thick. This keeper 

 used in all experiments with magnets of the same size. The mag- 

 net covered with sealing-wax varnish before it was coiled like the 

 others used in these experiments. It was coiled with 1 690 feet of 

 No. 13 copper wire, in 10 equal helices. The battery 1 foot square • 

 double cell charged with 1 in 50 sulphuric, 1 in 100 nitric acid;' 

 lifted at distance of ^ inch, 4| lbs. 



3 . gx 



Removed one of the coils, and used similar charge, it lifted at 

 ■j5q inch, 7^ lbs. 



Used thicker wires at the poles of magnet and batteries, 

 at ^ inch, 14ilbs. 



on ^^ 



Same magnet, charge, &c. one 

 coil of same wire, 150 feet ef- 

 fect at 1 perceptible, lifted in 

 contact 12^ lbs. 



Same magnet, &c., two coils, 

 300 feet, lifted at J^ . . 5f lbs. 



Same magnet, &c., three coils, 

 450 feet, lifted at 



f inch, 21 lbs. 

 i .... 31 

 1.... 41 



-^ qi 



Same magnet, &c., four coils, 

 600 feet, at 



f inch, 21 lbs. 

 i.... 31 

 1... 3| 

 ^ .... 12^ 



Same magnet, &c., five coils, 

 750 feet, 



1 inch, perceptible 

 &•••• 31 

 i .... 21 



*■••• 41 

 rV .... 121 



Same magnet, six coils, 900 ft. 

 1 inch, 3| lbs. 

 f .... 3* 

 i.... 3 

 i-.-. 71 

 T^....18i 

 bame magnet, &c., seven coils 

 1 050 feet. 



} barely 

 perceptible^ 



5| 



Same magnet, &c., eight coils. 

 1200 feet, 



1 inch, 7| lbs. 

 §.... 9| 

 i....41 

 *-...8f 



^ TV--..30i 

 bame magnet, &c., nine coils. 

 1350 feet, at 



^ inch, 51 lbs. 



f .... 61 



1 qi 



Tff 



H 



211 



