288 Prof. B. Stewart and Morisabro Hiraoka. [Jan. 30, 



Two distinct specimens with which we worked gave respectively — 



(1) . 6 -3004 



(2) . 6-2941 



The specific gravity of the fused iodide was found by the method 

 before described to be 



5 -2865. 



Thus the specific gravities corresponding to the five marked con- 

 ditions shown in the curve table are as follows : — 



Specific gravity at 0° C = 6 "297 



126° C. (octohedral condition) = 6 '276 

 „ ,, ,, (prismatic condition) = 6 '225 



200° C. solid = 6-179 



„ liquid = 5 '286 



II. " A Comparison of the Variations of the Diurnal Range of 

 Magnetic Declination as recorded at the Observatories of 

 Kew and Trevandrum." By Balfour Stewart, F.R.S., 

 Professor of Natural Philosophy in Owens College, Man- 

 chester, and Morisabro Hiraoka. Received January 10, 

 1879. 



In a previous paper by one of the authors (" Proc. Roy. Soc,," 

 vol. xxvi, p. 102) a table is given (Table II) exhibiting monthly means 

 of the Kew diurnal declination- range, corresponding to forty-eight 

 points in each year, or four for each month, that is to say, approxi- 

 mately one every week ; and, in another paper (" Proc. Roy. Soc," 

 vol. xxvii, p. 81), another similar table exhibits monthly means of 

 the Trevandrum diurnal declination- range for weekly points. In the 

 present paper these two tables are compared together. 



It became obvious to the writers, when engaged in making this 

 comparison, that the turning points in the curve, which represented 

 the variations of the Kew declination-range, were on the whole in 

 point of time before the corresponding points in the Trevandrum 

 curve. 



While this result might have been rendered evident by making the 

 numbers of the tables above-mentioned at once into curves, yet it was 

 found to become more apparent to the eye and freer from inequalities 

 by adopting a certain amount of equalization. 



Accordingly, the Kew and Trevandrum tables were transformed 

 into others, with the same time-interval between their numbers as in 



