28 Observations on the Temperature of the Ocean and 



pics, tlie s])ecific gravity of the water of tlie ocean, and its tem- 

 perature, and the tcniperatme of the atmosphere ; subjects of 

 •some importance in the natural history of our globe ; and in 

 ■which, 1 >iiow, you are interested. Incidentally I shall notice 

 the height of tht: barometer, the direction of the "winds, and the 

 state of the wcathei'. 



For the sake of brevity, I shall present tlie principal results of 

 my observations in the form of a Table, to u'hici) I shall add some 

 explanatory notes and general remarks. 



[The form of our pages does not admit of our inserting, at 

 length, the table here alluded to, which fills three (jiiarto pages ; 

 but this is the less necessary, as the remainder of the paper is 

 devoted to a detail of the experiments and their results — some 

 of which, especially vvhat relates to the diminished temperature 

 of sea-water in shallows, are highly deserving of the particular 

 attention of nautical men, as serving to announce the approach 

 of land. — Edit.] 



In all the experiments on the density of sea-water, the re- 

 sults of which are recorded in the journal, the water used was 

 taken from the surface of the ocean, in a large clean bucket. 

 The results introduced before we passed the equator the first 

 time, were procured at sea; the remainder, from 0° 12" south 

 lat. to Ceylon, were obtained on land from experiments made on 

 specimens of water preserved in well-corked phials. In the ex- 

 periments on board ship, as soon as the water was drawn, its tem- 

 perature was ascertained, and then it was immediately weighed. 

 The balance employed was not very delicate, for a verv delicate 

 instrument does not answer at sea, on account of the ship's mo- 

 tion ; however, it was pretty readily aflected by 1-1 0th of a 

 grain. The glass vessel in which the water was weighed, was 

 such a one as is commonly used at home; its capacity was equal 

 to about .SOO grains. In the experiments on shore, the same 

 vessel was used, l)ut a different balance, one of a more delicate 

 construction. I have chosen the temperature 80^ Fahrenheit, 

 for which I have calculated all the results, because it is nearly 

 the mean annual temperature of tiiis place, and nearly the mean 

 at sea, in the intertropical regions. 



The experiments made at sea I do not of course value so 

 much as those made on land: considered, however, merely as 

 approximations to the truth, which I am sure they are, the' re- 

 sults favour the general conclusion already formed by some phi- 

 losophers, that the ocean resembles the atmosphere in being 

 {c(Pler\s paribus) of nearly the same specific gravity throughout." 

 ^ And further, they lead to the conclusion, that the slight varia- 

 tions of specific gravity observed, do not regularly conform to 

 the difference of temperature. 



That 



