990 Dr. G. A. Shakespear on some 



Thus we have : — 



Normal. 



(Unsymtn. 

 or Odd). 



1st Chlorine atom C^ 21'8 



2nd Chlorine atom CI 11 — 



3rd Chlorine atom CP 11 21'4 



4th Chlorine atom Cl iv — 



5th Chlorine atom Cl iv 220 



6th Chlorine atom Cl v — 



Mean 21-8 



Abnormal. 

 (Symm. 

 or Even). 



19-5 

 19-1 

 19-4 



193 



If we arrange the Normal and Abnormal CI atoms on a 

 diagram and enclose the latter by a circle thus (Cl) 

 we find : — 



The abnormal Cl atoms are situated in the para positions 

 relative to each other, and the effect is to make one half of 

 the molecule substituted by Cl atoms normal and the other 

 half abnormal. 



CV. JS T ote on some Modifications in an ordinary Balance 

 tohich conduce to ease and quickness of weighing. By G. 

 A. Shakespear, M. A., D.Sc* 



HAYING had occasion during the last two years to use 

 a balance for rapid and somewhat accurate weighings, 

 I have been led to make certain modifications in the ordinary 

 instrument. The result has been so satisfactory in practice 

 that I think it may be worthwhile describing the arrangement. 

 In the use of a good physical balance the accuracy of 

 weighing is mainly limited by (a) the accuracy of the 

 weights, (b) constancy of temperature in the balance case, 

 (c) the accuracy with which the position of the rider can be 



* Communicated by Sir Oliver Lodge, F.R.S. 



