M. G. Wiedemann on Torsion. 



11 



When the wire in the temporary position was unloaded and 

 untwisted,, the permanent torsion was 319*5, and rose to 320 

 on a second torsion and detorsion of the unloaded wire. 



Therefore, if a load acts upon a wire while it is temporarily 

 twisted only up to a determined limit, an increase of the per- 

 manent torsion appears, similarly as above, at the shaking of 

 the wire. This takes place both when, after repeated tempo- 

 rary torsions, the weight is hung on the wire in the position 

 of the permanent and when in the position of the temporary 

 torsion. The unloading acts (though scarcely) in the same 

 direction. 



11. Loading during Variable Temporary Torsion. — Analo- 

 gous experiments were made on a brass wire of the same di- 

 mensions ; but the wire was temporarily twisted by a weight 

 (110 grams) freely, without striking, and the load was altered 

 in the position of the permanent torsion. In order to render 

 the differences of behaviour with different loads more conspi- 

 cuous, the wire was heated to 100° C. For this purpose it 

 was suspended, with its holdfasts, in a vertical brass tube of 

 15 millims. diameter, which was surrounded by a somewhat 

 shorter brass tube 6 centims. wide. The ends of the latter 

 were connected with those of the former by conical additions. 

 This entire heating-apparatus was divided lengthwise into two 

 halves, which were soldered together along the surface of the 

 longitudinal section, and were joined to one another by hinges, 

 in order that the wire might be more easily suspended in it. 

 Steam was introduced simultaneously into both halves, through 

 side tubes, from above, and carried off from beneath. The 

 following were the temporary and permanent torsions (P 

 noting the permanent torsion after alteration of the loading 

 weight) : — 



w. 



*v 



T. 



T j- 



Pi- 



1\-P r 



3220 

 >> 



» 

 >> 

 >» 

 »» 

 >> 

 >> 





1475 



1501 



1511 



1516 



1519 



1522 



1524 



1524-2 



1524 



1502 



1515 



1518 



1521 



1522 



1524 



1525 



1525-2 



1525-2 



96 

 120 

 130 

 137 

 141 

 144 

 146 

 148 

 149 



1406 

 1395 



1388 

 1384 

 1381 

 1380 

 1379 

 1777 

 1376 



9220 

 3220 

 9220 

 3220 

 9220 

 3220 



140 

 235 

 237 



265 

 272 

 285 



1570 

 1620 

 1636 

 1659 

 1673 

 1677 



1627 



1626-5 



1671 



1667 



1685 



1681 



241 

 242 



282 

 279 

 298 

 293 



1386 

 1384 

 1389 

 1388 

 1387 

 1388 



