520 



Prof. J. Trowbridge on the 



the accuracy with which determinations of the viscosity o£ 

 solutions can be made with this arrangement: — 



Average -01200 



Lithium Chloride Solution, Temperature 20°*75 C. 



i 



Pressure Time 

 (*)• (T). 



Correction. 



xio*. 



V- 



V 



(mean) 



/ 198-0 cm. 

 1198 2 „ 

 f 179-3 „ 

 1 1791 „ 

 / 151-0 „ 

 1151-2 „ 

 f 127-1 „ 

 1 127-0 „ 

 J 100-5 „ 

 1 100-0 „ 



57'2 sec. 

 56-4 ;, 

 62-8 „ 

 628 „ 

 731 „ 

 730 „ 

 85-6 „ 

 85-1 ., 

 106-6 „ 

 106-8 ., 



150 

 151 

 136 

 138 

 118 

 118 

 101 

 101 

 81 

 81 



•01201 1 

 •01198/ 

 •012041 

 •01197 r 

 •01200/ 

 •01200 / 

 ■011971 

 •01198 f 

 •01200 \ 

 •01203/ 



•01200 

 •01200 

 •01200 

 •01198 

 •01201 



XL VII. The Doppler JEfect in Positive Rays. 

 By John Trowbridge *. 



[Plate XIV.] 



rTIHE discovery of canal rays by Goldstein, and that of the 

 _L Doppler effect in these rays, marks an epoch in the 

 study of the discharge of electricity through gases ; for 

 before these discoveries the multitude of confusing effects 

 which arise in the space between the anode and the cathode 

 made it difficult to observe any translation movements. The 

 space, however, behind the cathode is comparatively free for 

 the passage of the positive ions. 



We now recognize, in addition to the positive rays behind 

 the cathode — the canal rays — retrograde positive rays which 

 are directed to the anode, or rather away from the cathode 

 in the direction of the anode t- 



This later discovery leads one to expect that the Doppler 

 effect should be found also between the anode and the 

 cathode. The result of my study shows that the effect does 

 exist in this region and indicates a movement away from the 

 cathode and toward the anode. 



* Communicated by the Author. 



f Wehnelt, Wied. Ann. A. 1899, p. 421 ; Eunge & Paschen, Wied. 

 Ann. lxi. 1897, p. 644; Paschen, Wied. Ann. xxiii. 1907, p. 247 

 Villard, Comptes JRendus, cxliii. 1906, p. 673 ; Goldstein, Phil. Mag. 

 March 1908, p. 372; Jacob Kunz, Phil. Mag. July 1908, p. 161; J. J 

 Thomson, Phil. Mag. Oct. 1908, p. 657. 



