1869.] 



On the Refraction-Equivalents of the Elements. 



49 



XXIII. " Fourth and concluding Supplementary Paper on the 

 Calculation of the Numerical Value of Eider's Constant." 

 By William Shanks. Communicated by Professor Stokes, 

 Sec. R.S. Received June 14, 1869. 



When w= 10000, we have 



1+5 + "3 + • . • i 6 1 o 0 == 



978760 G0360 44382 26417 84779 04851 60533 48592 62945 57772 



17183 89460 97673 221 + 

 Log e 10000+3^= 



9-21039 03719 76182 73607 19658 18737 45683 04044 05954 51509 



19041 33305 21764 185 + 

 Result of " Bemouilli's " = + 



•00000 00008 33333 33250 00000 03968 25392 65873 02344 87732 

 37845 49617 88207 355, &c. 



E= 



•57721 56649 01532 86060 65120 90082 40243 10421 59335 93995 

 35988 05773 64116 391. 



On comparing the value of E when n is taken 10000, with former values 

 already given, we cannot but conclude that the limits assigned to the value 

 of E in the Third Supplementary Paper have been confirmed, and that 

 nothing more seems requisite as to the determining of the numerical value 

 of this curious constant. 



XXIV. <c On the Refraction-Equivalents of the Elements." By J. H. 

 Gladstone, Ph.D., F.R.S. Received June 17, 1869. 



(Abstract.) 



This paper is a continuation of the researches on refraction which have 

 been already published by the author in conjunction with the Rev. T. 

 Pelham Dale*. 



It is divided into two parts — the data, and the deductions. The data 

 consist of the refraction-equivalents of some simple and many compound 

 bodies, calculated from the indices observed by various chemists and 

 physicists, or by the author himself ; together with a series of observations 

 on about 150 salts in solution. The method of examining these, and the 

 nature of the inference to be drawn from such experiments, have already 

 been explained in the Proceedings of the Royal Society, 1868, pp. 440- 

 444. 



The deductions consist of a comparison of the evidence bearing on each 

 elementary substance, beginning with carbon, hydrogen, and oxygen, 

 which were in the first instance determined by Landolt. In the case of 

 some elements all the means of calculation lead to the same number within 

 probable errors of experiment ; but in the case of others two or more 



. . * Phil. Trans, 1863, p. 317. 



VOL. XVI 1 1. E 



