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IV. On the Composition of Sea-water in the different parts of the Ocean. By Georg 
Forchhammer, Professor at the University, and Director of the Polytechnic Institu- 
tion at Copenhagen. Communicated by the President. 
Received July 28, — Read November 17, 1864. 
In the year 1843 a friend of mine, Mr. Ennis of Falmouth, sent me some bottles of sea- 
water from the Mediterranean, which I subjected to a chemical examination, a work 
which induced me to collect what other chemists had determined about the constitution 
of the water of the great Ocean. This labour convinced me that our knowledge of the 
composition of sea-water was very deficient, and that we knew very little about the 
differences in composition which occur in different parts of the sea. 
I entered into this labour more as a geologist than as a chemist, wishing principally 
to find facts which could serve as a basis for the explanation of those effects that have 
taken place at the formation of those voluminous beds which once were deposited at 
the bottom of the ocean. I thought that it was absolutely necessary to know with 
precision the composition of the water of the present ocean, in order to form an opinion 
about the action of that ocean from which the mountain limestone, the oolite and the 
chalk with its flint have been deposited, in the same way as it has been of the most 
material influence upon science to know the chemical actions of the present volcanos, 
in order to determine the causes which have acted in forming the older plutonic and 
many of the metamorphic rocks. Thus I determined to undertake a series of investi- 
gations upon the composition of the water of the ocean, and of its large inlets and bays, 
and ever since that time I have assiduously collected and analyzed water from the dif- 
ferent parts of the sea. It is evident that it was impossible to collect this material in a 
short time, and without the assistance of many friends of science, and I most gratefully 
acknowledge how much I am indebted to many distinguished officers of the Danish and 
British Navy, as well as to many private men, who were all willing to undertake the 
trouble carefully to collect samples of sea-water from different parts of the ocean, both 
from the surface and from different depths. I shall afterwards, when giving the parti- 
cular analyses, find an opportunity to mention the name of each of those to whom I am 
indebted for my material. 
While I was thus occupied for a space of about twenty years, another series of expe- 
riments closely allied to my work was commenced in England, and has partly been 
published under the able and scientific superintendence of Rear-Admiral FitzRoy. 
This most important series of observations regards the specific gravity of sea- water from 
the most different parts of the globe ; it comprehends a much more numerous series 
mdccclxv. 2 F 
