Ulster and Geitel Electrical Dissipation Apparatus. 



may be given as 



100 : 101 = 48° 47 ,: 3, 100 : 001 = 79° 16' 

 and 001 : 011 = 46° 25'' 75; 



or by /3=79° 16', and a : b : c= 1*587 : 1 : 1-070, 



The following are readings in important zones : — 



475 





Computed. 



Observed. 



! ■ 



100 : 201 



32 377 



o < 

 32 36 



302 



39 22 



40 11 



101 



48 47-3 



48 47 



001 



79 16 



79 15 



101 



116 24-6 



116 33 



100 : 522 



37 33 



38 7 



211 



43 9 



43 7 



233 



50 14 



50 7 



111 



59 7 



59 10 



122 



70 1 



70 



011 



82 37*5 



82 38 



122 



96 19 



96 2 



111 



108 44 



108 39 



211 



128 56 



128 58 



522 



136 11 



136 2 



101 : 212 



25 36 



25 35 



.. in 



43 46-6 



43 45 



Oil : 001 



46 25-75 



46 24 



Oil : 001 



,, 



46 35 



011:011 



92 51-5 



92 58 



I propose for it the name of Wiltshireite, as a token of 

 respect for the late Rev. Professor Thomas Wiltshire, Hon. 

 Sc.D., at one time Professor of Mineralogy in King's College, 

 London. 



Cambridge, 13 August, 1910. 



XL VII I. Discussion of Results obtained at Kew Observatory 

 with an Elster and Geitel Electrical Dissipation Apparatus* 

 from 1907 to 1909. By C. Chree, Sc.D., LL.D., F.R.S.* 



(From the National Physical Laboratory.) 



§1. AN ordinary Elster and Geitel dissipation apparatus 



XjL has been in regular use at Kew Observatory since 



the end of 1906, and the Annual Reports for 1907, 1908, and 



1909 have contained summaries of the results derived from it. 



* Communicated by the Author. 



