144 Royal Society : — Mr. Ellis on the Corrections for 



turned out to be native silver, having irregularly disseminated 

 through it patches or spots of black sulphide of silver. The 

 entire nugget weighed 100*83 grs., and had a specific gravity 

 of 10-77 at the temperature of 60° Fahr. 



Two analyses were made upon respectively 7*91 and 8'85 

 grs. of the specimen, and afforded — 



Silver ..... 7-75 8*67 



Gold ..... 0-02 0-02 



VJU1U \J \JA 



Sulphur .... 0-06 



007 



Insoluble. . . . 0-08 



0-09 



7-91 



8-85 



Or, calculated to one hundred parts, — 





Silver .... 97-84 



97-98 



Gold .... 0-28 



0-22 



Sulphur ... 0-75 



0-79 



Insoluble . . . 1-13 



1*01 



100-00 



100-00 



XIX. Proceedings of Learned Societies, 



ROYAL SOCIETY. 



[Continued from p. 73.] 

 May 18, 1865. — Major-General Sabine, President, in the Chair. 

 ri^HE following communication was read : — 

 JL "On the Corrections for Latitude and Temperature in Baro- 

 metric Hypsometry, with an improved form of Laplace's formula." 

 By Alexander J. Ellis, F.R.S. 



Adopting the notation in Table I. (p. 154), and the data of M. 

 Mathieu (Annuaire du Bureau des Longitudes, 1865, p. 321), 

 Laplace's hypsometrical formula, after some easy transformations, 

 becomes 



^-H^pogB-logS-'OOOO;. (M'-m').]x[500+A' + a'] 

 f 18336 / 15926 \1 r A+H x i 



L500.(l-*cos2L)'V 6366198/J [_ 6366198J 

 = [log B-log 6--00007 . (M'-w')] X [500+A' + «'] 



K =8t»*_ + K=S. . w 



1 — g cos 2 L R x v ' 



=W.T'.G 2 + o 1 -V 1 . . (6) 



In the last term in (a), h 1 — H x represents the product of the three 

 preceding factors, W . T' . G 2 ; and g is left for the present undeter- 

 mined. 



If y be the total increase of gravity in proceeding from the equator 

 to the pole, the coefficient g= y-f- (2 + y)*, for which most writers 



* The term 1— z cos 2L represents the ratio of the gravity at latitude L°, to 

 the gravity at latitude 45°, which on the spheroidal theory of the earth's shape is 



[l+y.(sinL)*]-(l-}-! 7 ), 

 and tins gives the above value of z. 



