Sun-Spots, Atmospheric Pressure, and the Sun's Heat

Abstract

THE question whether the atmospheric pressure varies with the spotted surface of the sun was noticed by me in a paper on the Isobars within the British Isles. I could not, however, find any appearance of a decennial law in the yearly mean pressures: such a relation presented itself however in the varying directions of the isobars (Proc. Roy. Soc, 1877, p. 599). The yearly mean pressures in our latitudes are subject to large irregular variations, and several decennial periods would be requisite before these could be neutralised in the decennial means. As the irregularities are much smaller within the tropics, I did not fail to examine the yearly means for India which were in my possession at the time; and I found their variations very small and apparently without any relation to the decennial period. Mr. F. Chambers's interesting letter to NATURE (vol. xviii. p. 567) has induced me to make a more careful study of the Indian observations at present before me.