Prof. Gr. Wiedemann's Magnetic Researches. 



63 



of this thread was attached to a fixed hook, the end J 6 passed 

 over a fixed pulley to the windlass z. If by turning f the 

 pulley 7) was gradually lowered, the weight 7 y 1 at first acted 

 upon the torsion- circle until the weight $ ft reached the other, 

 when both together acted in twisting the wire. The horizontal 

 wires soldered to the weights rested against fixed vertical wires, 

 and so prevented the turning of the weights with the threads 

 carrying them. By winding up the pulley tj, the torsion cor- 

 responding to the weights /3 ft + 7 71 and that corresponding 

 to the weight yji alone could be determined. The weights 

 were always raised and lowered very slowly, so that they 

 produced their effect without any jar. The reading each 

 time was not taken until, after putting on the weights, the 

 temporary torsion did not perceptibly change any more. The 

 weight y y! (1) weighed 61-8 gr., £ ft +7 ?! (1) + (2) 125*9 gr. 



As before, the torsions were read off by means of a tele- 

 scope in a mirror, which was attached to the lower clamp of 

 the wire subjected to torsion, and in which the image of a 

 semicircular scale, placed round the wire as axis with a radius 

 of 1 metre, was reflected. The following tables contain some 

 of the results obtained. The first column gives under G the 

 weights used to produce the torsion, the following columns 

 give the corresponding torsions successively obtained. The 

 experiments were continued until the same torsion was 

 obtained upon renewed action of the weights. 



I. Brass wire, 2 millim. thick and 51*8 millim. long, 

 stretched before loading by a weight of 8350 gr., and an- 

 nealed under a load of 8000 gr. 



G. 



I. 



II. 



III. 



IV. 



V. 



VI. 











223-5 



242-5 



255-5 



264-2 



267-3 



(1) 



684-0 



904-5 



924-5 



937-0 



9430 



9470 



(l)+(2) 



1691-7 



17050 



1706-7 



17135 



1714-0 



1714-5 



CO 



9730 



989-5 



693-5 



990-5 



1000-5 



1001-5 



G 



VII. 



VIII. 



IX. 



X. 



XI. 







2695 



273-0 



2730 



275-0 



281-0 



(1) 



949 



950-5 



9520 



953-5 



957-2 



(l) + (2) 



1714-5 



1714-5 



1718-5 



1719 5 



1721-5 



(1) 



1002-5 



1002-5 



1005-0 



1004-3 



1000-5 



After ten repetitions of the increase and decrease the 

 deflections obtained were : — 



