ME. J. PEESTWICH ON SUBMAEINE TEMPEEATUEES. 
59 : 
him and Dr. Horner in the tropical regions of the Pacific* * * § and the Sea of Okhotsh. 
We have no description of his water-bucket, and are therefore without means of 
judging of the exact value of the results. The more numerous experiments made, on 
the other hand, by Dr. Horner f with Six’s thermometer admit of correction. 
A subject of so much interest did not escape the attention of Scoresby ; and he gives 
a Table of the twenty-four observations made by him in the seas around Spitzbergen, 
during his several voyages to the Arctic Ocean between 1810 and 1822, at depths 
varying from 78 to 4566 feet J. He made use of an apparatus (no doubt based on that of 
Hales) consisting “of a cask capable of holding 10 gallons of water, composed of 2 inches 
of fir plank, as being a bad conductor of heat.” Each end of the cask was furnished 
with a valve ; these were connected with a wire so as to move simultaneously. They 
opened in descending and closed in ascending. The cask was allowed to remain down 
half an hour, and was hauled up briskly. A common thermometer was then used to ascer- 
tain the temperature of the water so brought up. This machine soon, however, got out of 
order, and he had one cast in brass, 14 inches in length by 5J inches in diameter, 
which he called a marine diver. This he employed in all his experiments on and after 
the 1st May, 1811. A Six’s thermometer was enclosed, which could be read off through 
two glass sides in the “ diver ” on coming to the surface. The weight of the machine 
was 28 lbs. He recognized in these seas a uniform though slight increase of tempera- 
ture from the surface to the greatest depth he attained, the temperature at the surface 
being generally 28° to 29°, and increasing in descending to 36° and even 38° (uncorrected). 
In a subsequent voyage he gives, however, an experiment made 7° or 8° further south, 
and off the coast of Greenland, in which the reverse held good ; the surface-temperature 
being 34°, and at a depth of 678 feet 29° §. 
Objections have been raised to Scoresby’s experiments, on the ground that they do 
not accord with those of Martins and Bravais, which were made with more exact 
modern instruments. But these observers themselves accept Scoresby’s observations as 
true, subject to small corrections. The differences between them are, in fact, more 
apparent than real, and arise chiefly from the circumstance that their observations were 
made in the months of July and August, when the temperature of the air averaged from 
35° to 45°, and that of the surface-water from 38° to 42°, whereas Scoresby experimented 
in April and May, when these had temperatures respectively of 20° to 34° and of 28° to 
30°, so that the relative differences between the surface and the deep waters are neces- 
sarily very different in the two cases. In the experiments at depths below 2000 feet 
there is little discordance after applying the corrections employed by Martins and 
Bravais. The latter, however, took no depth exceeding 2854 feet, while Scoresby gives 
* Yoyage round the World in the years 1803-6. English translation. London, 1813, vol. i. pp. 187 & 203. 
t Horner’s observations are recorded hy Gehxer (note, p. 589). They are given under his name, and not that 
of Krusenstern, in the Tables. See also the original work of Krusenstern. 
± Account of the Arctic Eegions. Edinburgh, 1820, p. 187. 
§ Journal of a Yoyage to the Northern Whale Fishery in the year 1822. Edinburgh, 1823, p. 237. 
