Barometric Depression

Abstract

IN Mr. Monck's article on barometric variations in NATURE of 21st inst. there is a serious mistake about the theory of trade-winds. He says the trade-winds would probably extend to the poles were it not that the parallels of latitude become so narrow before reaching them. The trade-winds are east winds; and if, as is certainly the case, the only motive power acting on the earth's atmosphere is the sun's heat, it follows from the law of the conservation of rotation that the total force of the east and west winds must exactly balance each other. This must be the case even were the earth of some other form than a sphere.