208 Dr c Gladstone on some Recent Determinations 



myself and the late Pelham Dale. It agrees, as far as D is 

 concerned^ with a determination by Becquerel. R E = 16*86. 

 Sulphur in the gaseous condition was determined by Le Roux 

 in 1861. The specific refraction was calculated out by me 

 shortly afterwards, and recently by Nasini and Costa*. I 

 give their number for the atomic refraction in the Table. 



The sulphur in solution is from five determinations of this 

 element dissolved in carbon bisulphide which I made some 

 years ago with another object, and which have never been 

 published. The solutions contained from about 22 to 27 

 per cent, of sulphur. Two determinations of somewhat weaker 

 solutions were lately published by Nasini and Costa, and were 

 practically identical with mine. The refraction of 17'3 for 

 the line 7 is deduced from their figures alone. 



The four last lines give the values of sulphur reckoned 

 from its simplest compounds. 



In the case of bisulphide of carbon the figures in the Table 

 are derived from my own most recent observations, which 

 agree closely with those of other observers. The deduction 

 made for the atom of carbon is 5*0 for the line A, 5'26 for the 

 line H, and proportional numbers for the intermediate lines. 



In the case of bichloride of sulphur the calculations have 

 been made from the observations of Costa ; and in that of 

 chloride of sulphur from those of Haagen, Becquerel, and 

 Costa, which fairly agree. The refraction due to an atom of 

 chlorine is assumed to be 9*95 for the line C, and 10*05 for 

 the line D. Costa, in treating of these substances, has adopted 

 a slightly smaller value for chlorine. 



In the case of the bromine compound the sulphur is cal- 

 culated from Becquerel' s observations, taking the value for 

 bromine at 15*35. 



The figures for sulphur derived from these various sources 

 are very similar. I doubt, however, whether the sulphur 

 dissolved in bisulphide of carbon and the sulphur which forms 

 part of that compound do exert exactly the same influence 

 upon the rays of light. If we were to reckon the value of 

 carbon in bisulphide of carbon by deducting the value found 

 for sulphur in solution, we should get for A, 36*6 — 31-0 = 5*6, 

 a higher figure than we ever find for carbon in a saturated 

 compound. The difference would be still greater if reckoned 

 by Lorenz's formula. 



The accordance of the dispersion as exhibited throughout 

 the Table is worthy of notice. 



From the elaborate paper of Nasini and Costa, already 

 referred to, it would appear that in some organic compounds, 

 * Universita Inst. Ch. Roma, 1891. 



