the IVater of the Sea. 131 



ments which he made successively in the neighbourhood of 

 the equator at the depth of 300, 500, 1200, and 2144 feet. 



This consequence, which no doubt is new and very in- 

 teresting, results, namely, that the temperature of the water 

 of the sea decreases in proportion to the depth. The dif- 

 fere:ice obtained by M. Peron in his last observation at the 

 dept'i of 2144 feet, was 19'^ of Reaumur between the tem- 

 perature of the surface and that at this depth. 



Having given the result of his particular observations, 

 the autlvfr examines the experiments of the same kind 

 whicli were made before. " If we except," says lie, ^' the 

 celebrated traveller whose return has excited universal joy 

 among all the friends of science, and who attended also to 

 this object, but whose results and apparatus I am still un- 

 acquainted with*, three persons only have made accurate 

 observations in the open sea on the temperature of the wa- 

 ters, viz. Irving, Forster, and myself. By a very uncom- 

 mon accident, our experiments were repeated at three of the 

 most opposite points of the globe. By Irving, durino- the 

 voyage of the honourable Mr. Phipps, afterwards lord Mul- 

 grave, to the North Pole; in the expedition of captain Cook 

 to the South Pole, they were continued by Forster to the 64th 

 degree south,' beyond which no navigator had been able to 

 advance ; and I myself, placed, as I may say, between these 

 extremes, made all my experiments in the neighbourhood 

 of the equator. It would certainly be difficult"'to lind any 

 other fact in physics where so many points of comparison 

 can be enumerated ; and yet we shall find the results of 

 these different experiments reproduced, every where analo- 

 gous to those which I shall here exhibit." 



In Forster's experiments, indeed, we find that the tem- 

 perature of the sea decreases successively from the 16th of 

 Reaumur to the term zero of the same thermometer, and 

 It continually decreases the greater the depth. The inge- 

 nious experiments of Dr. Irving; reproduce the same results 

 with still more interest, since at tlie depth of 3,900 feet he 

 obtained two degrees below zero of Reaumur's scale. 



M. Peron then takes a rapid view of the very incomplete 

 <?xperiment3 of Ellis, Wallis, Bradley, and Baldh, and the 

 anonymous ones collected by Kirwan : he is satisfied with 

 obser\'ing, that they all concur to confirm the principal re- 

 sults of his own expernucnts, and those of Forster and Ir- 

 >ing. He concludes with a gen^'ral view of the same re- 



• Mr. Humboldt was still at BourJcaux. 



I 2 suits, 



