its Relations to Temperature. 



Table 1. — Residual Twist. Rods Glass-hard. 



No.- 



Annealed 

 at 



h 



Aj 



A 2 ■ 



Twist. 



A and B. 

 Z,=31 cm 



2p=0-082 cm 



100° 



o-oo 



1-08 

 2-08 

 3-58 



o-o 



57° 



64 



70 



- 



180°-7° . 



Cand D 

 Z=31 cm 



2p = 0-082 cm 



100° 



o-oo 



0-17 

 0-67 

 2-00 



- 



—o-o 



-36° 



-64 

 -70 



180°-10° 



E andF 

 £=31 cm 

 2p=0-082 cm 



190° 



o-oo 

 o-io 



0-80 



- 



— 00 



-123° 



-153 



180° — 25° 



Gand H 



£=31 cm 

 2p=0-082 cm 



190° 



o-oo 

 o-io 



1-00 



- 



—o-o 



-104° 

 — 130 



180°-2° 



I and J 



i=31 cm 



2p=0-082 cm 



190° 



o-oo 



0*08 

 1-20 







39° 

 57 







52° 

 ■ 69 



90°-10° 



K andL 

 Z=31 cm 



•2p=0-082 cm 



360° 



o-oo 



0-30 





 166° 





 148° 



180°-20° 



M and N 

 i=31 cm 

 2p=0-082 cm 



360° 



o-oo 



0-30 



• 



180° 





 166° 



180°-10° 



andP 

 Z=3 l cm 



2p=0-082 cm 



360° 



o-oo 



030 







77° 







71° 



90° — 8° 



Q and R 

 £-31 cm 

 2p = 0-043 cm 



360° 



000 

 030 



o-oo 



0-30 





 156° 





 165° 





 54° 



180°-8° 



S and T 

 Z=31 cm 

 2p=0-043 cm 



360° 







48° 



180'-2° 



This table contains results which may be expressed as fol- 

 lows : the viscous detorsion produced by the action of any 

 temperature on a twisted system of glass-hard steel wires, in- 

 creases gradually at a rate diminishing continuously through 

 infinite time, diminishing slowly in case of low temperatures 

 ( < 200°), rapidly at first and then again slowly at high temper- 

 atures (> 200°) ; so that the residual twist corresponding to any 

 given temperature is reached asymptotically. Moreover, the 

 strain carried by the glass-hard twisted system is almost com- 

 pletely annulled when the temperature at which annealing 

 takes place exceeds 350°. These results are so strikingly 

 similar to the thermoelectric effect* produced by annealing 

 glass-hard steel, that the present purely mechanical result may 



* U. S. Geol. Surv., Bull. 14, pp. 55, 95, 1885. 



