292 



whilst on the other hand, winds charged with vapour would have hut 

 little effect ; and a heavy fall of rain, particularly in equatorial parts 

 of the Ocean, where the sea is so little disturbed, would very sensibly 

 diminish it. It is also very sensibly less in the vicinity of the coast, 

 particularly when the latter is of a shoal character, as is the case 

 between the River Plate and the Strait of Magalhaens, where the 

 whole extent is fronted by a bank having from 30 to 50 fathoms of 

 water. 



The mean specific gravity of the water of the South Pacific, con- 

 tained between the parallels of 10 and 40, is 1026*48, and between 

 40 and 60 it is 1026-13. 



The results obtained by the author are then compared with the 

 following, viz. 



Observations made on board the 'Hamlet' in 1849, during a 

 voyage from Sydney to England. 



Observations made on board the ' Thomas Arbuthnot' in 1849 and 

 1850, during a voyage from England to Sydney. 



Specific gravities of specimens of water collected by Captain 

 J. Elphinstone Erskine, R.N., of Her Majesty's Ship ' Havannah,' 

 the Senior Officer on the Australian Station, during a visit to New 

 Caledonia, the Loyalty Islands, and to those at the south-eastern 

 end of the Solomon Islands. 



Specific gravities of specimens of water collected by the late 

 Captain Sir James Everard Home, Bart., R.N.,C.B., of Her Majesty's 

 Ship ' Calliope,' the successor of Captain Erskine in the command 

 of the Station, who visited the Friendly and the Fidjee Islands. 



Specific gravities of specimens of water collected by Mr. Simpson, 

 who commanded a trading vessel between China and Sydney, from 

 the Indian Ocean between the Strait of Sunda and the Latitude of 

 36 South. 



II. " On the Existence of Silver in Sea-water." By FREDERICK 

 FIELD, F.C.S. Communicated by MICHAEL FARADAY, 

 Esq., D.C.L., F.R.S. &c. Received October 23, 1856. 



In a paper first published by MM. Malaguti, Durocher, and 

 Sarzeaud in the ' Annales de Chimie et de Physique,' xxviii. p. 129, 



