of sea waters, in different parts of the ocean , &c. 195 
It would hardly be consistent with the plan which I have 
followed in this inquiry, to enter minutely upon the analysis of 
the waters of individual seas, since, instead of dwelling on 
analytical details, I have rather aimed at presenting an ex- 
tensive and comparative view of the subject, for the pur- 
pose of drawing certain general inferences. Yet as my ex- 
periments were made with care, and appear from their con- 
sistency with each other, to justify some degree of confidence 
as to the accuracy of their results, it may not be out of place to 
select from the above table some individual water, with a view 
be noticed. The smell of the specimens put into my hands by Captain Hall, 
was exceedingly hepatic, like that of a strong solution of sulphuretted hydrogen, 
and this water formed with silver a black precipitate. I twas clear and trans- 
parent ; but had a greenish yellow colour. Nitric acid made it milky, and 
precipitated sulphur from it. When boiled it gave out sulphuretted hydrogen 
gas, and deposited a yellowish sediment, which proved to be carbonate of lime, 
in the proportion of 0.7 grs. for 500 grs. of the water, and without any sulphur 
being mixed with the sediment. The interior of the bottles was found blackened, 
so as to render the glass quite opaque ; but the black film was easily wiped off, and 
the glass was not permanently stained. After evaporating the water to dryness, the 
residue dissolved readily in water, with the exception of the carbonate of lime above 
mentioned, and the solution now precipitated silver perfectly white. In other respects 
the saline contents of this water did not differ from those of other seas. Its specific 
gravity was low (1022.9), but the salts, with the exception of a small deficiency in 
the magnesia, were the same as usual. The water was first put by Captain Ha l l 
into a green-glass bottle ; but it was, some months afterwards, transferred into several 
white-glass phials, having glass stoppers, all of which exhibited the appearance above 
described. There is something in this developement of sulphur in sea water which is 
by no means well understood. Of two specimens brought from the same spot, and by 
the same individual, I have sometimes observed that the one had a smell of sulphu- 
retted hydrogen, while the other was perfectly free from it. In the former case the 
cork was commonly blackened and decayed. 1 therefore suspect that in some instanc^ 
the cork gives the impulse to the formation of sulphuretted hydrogen ; but in others, 
and probably in the Yellow Sea, this change is likely to be owing to the presence of 
some vegetable or animal matter, and its gradual action on the saline water. 
