10 M. G. Wiedemann on Torsion. 



of the beaker. The total weight of the metal ring hanging to 

 the wire, with its holdfast &c, as well as that of the beaker 

 filled with water up to the end of the glass tube, amounted to 

 3220 grams. 



9. Loading during Permanent Torsion. — First, an annealed 

 brass wire, of 2 millims. thickness and 480 millims. length, 

 was twisted ten times, five minutes each time, up to the stroke 

 of 2430 scale- divisions, while it was loaded beneath with 3220 

 grams. The permanent torsions, five minutes after each de- 

 torsion, were : — 



I. II III. IV. V. VI. VII. VIII. IX. X. 



721 733 737 740-8 743-2 745-2 747 748 749 750 



6000 grams of water being then admitted into the beaker 

 suspended beneath the wire while the latter ivas in the posi- 

 tion of permanent torsion, the permanent torsion was reduced 

 by the shaking to 748*7. If the wire was then again brought 

 to the previous temporary torsion and untwisted, the perma- 

 nent torsion rose to 764 — and on a second torsion and detor- 

 sion, to 770. When the water was let out, the permanent 

 torsion was lowered to 762*6 by the shaking, but rose again 

 up to 765 at a single torsion and detorsion. 



10. Loading during Constant Temporary Torsion. — When 

 in like manner a new wire was temporarily twisted and un- 

 twisted to the stroke of 1952 scale-divisions ten times by the 

 lesser loading, the permanent torsions amounted to : — 



I. II. III. IV. V. VI. VII. VIII. IX. X. 

 351 387-5 401 409 434 447"5 420-2 422-3 424 425-2 



The wire was then again twisted up to striking; and ivhile 

 it was in the position of the temporary torsion, 6 kilogs. of 

 water was admitted into the beaker with which it was loaded. 

 After the detorsion the permanent torsion had risen to 452 ; 

 after a repeated torsion and detorsion, to 461. 



The same experiments were performed inversely ; that is to 

 say, the wire was first twisted and untwisted ten times while 

 loaded, and was then unloaded in the positions both of the 

 permanent and of the temporary torsion. The results were : — 



I. Loaded wire temporarily twisted up to 2283 scale-divi- 

 sions ten times. 



I. II. III. IV. V. VI. VII. VIII. IX. X. 

 P... 600 644 651 655 658 660-6 662-2 663-5 664-8 665-8 



While the wire was in the permanent position the water was 

 let out, when P fell to 662. The wire being again twisted up 

 to 2283 scale-divisions, and untwisted, without loading, P 

 rose to 664 — and on a second torsion and detorsion, to 665*6. 



11. Loaded wire ten times temporarily twisted to 1839 

 scale-divisions. 



I. II. III. IV. V. VI. VII. VIII. IX. X. 

 P .350 385 397 304 309 312-5 315 316-8 318 319-5 



