26 SIXTH REPORT. — 183G. 



Same magnet, batteries, &c., all the coils remaining on the bar ; 

 average of a number of experiments : 



lbs. lbs. 



1 of the coils connected with 2 helices forming one, 5| 



battery 2^ 3 4^ 



2 3i 4 7i 



3 7i 5 6i 



4 Hi 6 



5 13i 1 4| 



6 18| 



7 22| 



8 26| 



9 19i 



Second Series. 



No. 1. — Horse-shoe iron bar, 9f inches long, 1| diameter, sur- 

 mounted at poles by ground discs, 4 inches diameter, ^ thick. 

 Keeper, 9 long, 4^^,^ wide, and | thick, coiled with oCO feet No. 

 15 iron wire, in five equal helices; charge, 1 in 50 sulphuric, 1 in 

 100 nitric acid ; 



at Ya i"c^> ^^ lifted 6 lbs. 

 Magnet, No. 2. — Same size, coiled with 500 feet No. 13 copper 

 wire in 5 coils ; same charge &c. : 



at A inch, it lifted 4 lbs. 

 -t 7i 



16 ". 2 



Magnet, No. 3. — Same size, coiled with 500 feet No. 12 iron wire, 

 at ^ inch, it lifted 1^ lbs. 

 1 4 



Fig. 2. 

 Magnet. No. 4. — Same <x_^ V-^ ®^^^' ^"* discs or poles 

 replaced by pins, retaining Tnj y^j the coils on the bar 500 

 feet No. 12 iron wire. Same ^ ^ <^*"-^ battery, &c. Hardly 

 any effect. 



Thikd Series. 



In the other series, the charge is changed before every experiment. 

 In this, the same charge is retained throughout. 



Magnet, No. 1. — Soft iron square horse-shoe bar, 7^ long, i 

 square, coiled with 90 feet No. 13 copper wire. 



Magnet, No. 2. — Cast iron, same size and helix. 



Magnet, No. 3. — Same size, but round bar diameter ^, coiled with 

 90 feet of same wire, in two lengths each, distributed over the whole 

 bar. 



Magnet, No. 4. — Same size and coiled with 60 feet, in two he- 

 lices ; one on each half of bar ; number of coils increasing from 

 centre to poles ; charge 1 in 50 sul])., 1 in 100 muriatic acid ; keeper, 

 5| inches long, | wide, ^ thick. 



