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the vertical circulation, and the north and south movement, advocated by 
him, and then the revolution of the globe will make it, as has been long 
recognised, a westward movement in the tropics and an eastward in the 
middle and higher temperate latitudes, such as is found, in fact, in all oceans. 
Then, secondly, whenever, in the flow of these waters, they approach the 
continents, where the depth diminishes, the rate of flow will be increased in 
proportion (approximately) to the decrease of depth : and hence comes the 
stream east, not only of North America and there called the Gulf Stream, 
but of South America, and also those east of Asia and of Australia ; and also 
that in the higher latitudes west of South America. The Gulf Stream and 
all those other streams are parts of the general system, modified by proximity 
to the continents ; the action of the trades is not in any case their origina- 
tion, though it may well be their accelerator. Neither is an Indian Ocean 
current the origin of the current in the South Atlantic up the west side of 
Africa, though contributing to it. Dr. Carpenter also combats Mr. Croll’s 
position, with regard to the 1 thermal work of the Gulf Stream.’ ” 
The Temperature-equilibrium of an Enclosure in ivkich there is a Bodij in 
Visible Motion. — This is the subject of one of the most important papers 
brought before the British Association at Edinburgh, by Professor Balfour 
Stewart, of Owen’s College, Manchester. He said — taking the illustration of 
the room in which they were assembled — they knew that in an enclosure, 
the walls of which are kept at a constantly uniform temperature, every sub- 
stance will ultimately attain the very same temperature as those walls ; and 
we know also that this temperature-equilibrium can only be brought about 
by the absorption of every particle being exactly equal to its radiation, an 
equality which must separately hold for every individual kind of heat which 
the enclosure radiates. This theoretical conclusion is supported by numerous 
experiments, and one of its most important applications has been the analysis 
of the heavenly bodies by means of the spectroscope. The Professor then 
asked the Section to suppose that in such an enclosure we have a body in 
visible motion, its temperature, however, being precisely the same as that of 
the walls of the enclosure. Had the body been at rest, we know from the 
theory of exchange that there would have been a perfect equilibrium of 
temperature between the enclosure and the body ; but there is reason to 
believe that this state- of temperature-equilibrium is broken by the motion of 
the body. Eor we know, both from theory and experiment, that if a body, 
such, for instance, as a star, be either rapidly approaching the eye of an ob- 
server or receding from it, the rays from the body which strike the eye will 
no longer be precisely the same as would have struck it had the body been 
at the same time at rest, just as the whistle of a railway engine rapidly 
approaching an observer will have to him a different note from that which it 
would have had if the engine had been at rest. The body in motion in the 
enclosure is not, therefore, giving the enclosure those precise rays which it 
w T ould have given had it been at the same temperature and at rest ; on the 
other hand, the rays which are leaving the enclosure are unaltered. The 
enclosure is therefore receiving one set of rays and giving out another, the 
consequence of which will be a want of temperature-equilibrium in the en- 
closure ; in other words, all the various particles of the enclosure will not be 
of the same temperature. The consequence will be we can use those particles 
