82 ANNUAL OF SCIENTIFIC DISCOVERY. 



mechanical equivalent of heat. In 1845, he published his Memoir on 

 4 Organic Motion,' and applied the mechanical theory of heat in the 

 most fearless and precise manner to vital processes. He also embraced 

 the other natural agents in his chain of conservation. 



" When we consider the circumstances of Mayer's life, and the pe- 

 riod at which he wrote, we cannot fail to be struck with astonishment 

 at what he has accomplished. Here was a man of genius working in 

 silence, animated solely by a love o/ his subject, and arriving at the 

 most important results some time in advance of those whose lives were 

 entirely devoted to Natural Philosophy. It was the accident of bleed- 

 ing a feverish patient at Java, in 1840, that led Mayer to speculate on 

 these subjects. He noticed that the venous blood in the tropics was 

 of a much brighter red than in colder latitudes, and his reasoning on 

 this fact led him into the laboratory of natural forces, where he has 

 worked with such signal ability and success. Well, you will desire to 

 know what has become of this man. His mind gave way ; he became 

 insane, and he was sent to a lunatic asylum. In a biographical dic- 

 tionary of his country it is stated that he died there ; but this is incor- 

 rect. He recovered, and, I believe, is at this moment a cultivator of 

 vineyards in Heilbronn." 



EFFECTS OF THE EARTH'S ROTATION. 



M. Foucault's beautiful experiment, by which, through the medium 

 of a pendulum, the rotation of the earth on its axis may be said to have 

 been rendered palpable to our senses, has had the effect of calling at- 

 tention to a great many other phenomena going on on its surface, into 

 which it enters as a modifying cause. To say nothing of those great and 

 general facts of the oblateness of its figure, and the trade-winds which 

 Newton and Hadley explained on this principle, we have seen the 

 phenomena of Cyclones reduced to a dependence on this cause, com- 

 bined with local disturbances of temperature ; and, tracing the same 

 cause into its still more local, and, so to speak, miniature sphere of action, 

 it is recognized that the influence of the earth's rotation cannot be left 

 out of consideration in the accurate pointing of long-range artillery, 

 inasmuch as in a flight of five miles, occupying twenty -five seconds of 

 time, it would carry a projectile pointed northwards, about forty-five 

 feet to the east, and southwards as much to the west, (. e. in both cases 

 toward the right hand) of its line of fire. Pursuing the action of this 

 cause into geographical inquiries, it has been argued that the action of 

 a river flowing directly northwards or southwards, or indeed in any 

 direction considerably inclined to the parallel, cannot be equal on its 

 right and left banks ; and that in either case (and indeed, whatever 

 be the direction of the stream, if at all so inclined), in the northern 

 hemisphere, the rotatory motion of the earth will have the effect of 

 driving the water against the right bank of the river, and thus causing 

 it to exert a greater erosive action on that than on the opposite side ; 

 and vice versa in the southern hemisphere ; the effect in both being 

 more powerful the higher the latitude ; and nil on the equator. On 

 the other hand, it has been contended, that although, theoretically 

 speaking, this is a real cause, (a vera causa), yet the amount of ero- 

 sion thence arising must be far too small to produce any sensible ten- 

 dency in rivers to shift their courses to the right, or to eat away 



