Barometric Pressure and Sun-Spots

Abstract

IN his letter to NATURE, vol. xviii. p. 567, on “Sun-Spots and Weather,” Mr. Fred. Chambers has shown that the curve of mean barometric pressure at Bombay throughout the year varies with the inverted sun-spot curve. Taking this fact together with the commonly-received idea that the annual variation of barometric pressure in Central Asia is due to the corresponding annual variation of solar radiation, he thence concludes that “the sun is hottest about the time that the spots are at a maximum, and coldest about the time when they are at a minimum.” Now, even if the validity of the logical process by which “secular” is substituted for “annual” in this argument be admitted to hold in a general way, have we any reason to suppose that the atmospheric conditions at Bombay, a marine station on a peninsula, can be adequately taken to represent those which prevail in the centre of the Asiatic continent, or that they approximate to the latter to any greater extent, or even as much as those at St. Petersburg, for example?