Investigation of the Simple Cohct 

 Table III. 



'213 



In this case in order to sunder the wires currents must be 

 reduced, i. e. resistance must be increased. 





Resistance to 



Resistance to 



Kemarks. 



overcome 



overcome 





torsion. 



sticking. 



A damp day. •> 



710 



720 



Contacts clean. j 



710 



720 





710 



740 





710 



740 



i 



710 



760 



Table IV. 



Remarks. 



Resistance to 



overcome 



torsion. 



Resistance to 

 overcome 

 sticking. 



A damp day. T 

 Current passing. J 







Breathe on once — *, 



2550 



1000 



1 



2570 



2530 





2570 



2560 





2570 



2560 



All the following observations were taken when the air was 

 dry, the extra precaution being taken to rub the wires with 

 well-dried blotting-paper before using, and to repeat this 

 process every few minutes. 



We cannot suppose that the condensed oxygen and nitrogen 

 on the surfaces, which played such a prominent part in the 

 recent observations * of Mr. Spiers, can be in liquid form, 

 and therefore cause surface-adhereuce, though, as shown 

 above, the average pressure over the area of contact is 

 200 atmos; for, as pointed out by Prof. Oliver Lodge t, their 

 critical temperatures are far too low for this to be possible in 

 the usual sense. But it will be seen presently that they seem 

 to produce a marked effect on the resistance of the contact, 

 when the pressure is small. 



* Phil. Mag. Jan. 1900; Proc. Phvs. Soc. 1900, p. 39 &c. 



t Phys. Soc. Pres. Address, Feb. 1900; Phil. Mag. xlix. (1900). 



