XXI. Researches on solar physics.—No. II. The positions and areas of the spots observed at Kew during the years 1864, 1865, 1866, also the spotted area the sunʼs visible disk from the commencement of 1832 up to May 1868

Abstract

20. In a paper presented to the Society and published in the Philosophical Transactions for 1869 (vol. clix. p. 1), we have given a full description of the method adopted by us for ascertaining the positions and areas of the various sun-spots observed at Kew, and we have likewise, in Tables II. and III. of that paper, given the areas and the positions determined after the method described by us, for the various sun-spots of the years 1862 and 1863. In the present paper we give the same elements for the years 1864, 1865, and 1866, forming Tables II. and III., so that these Tables in our present paper form a continuation of the Tables bearing the same number in our previous paper. We have stated elsewhere that Hofrath Schwabe, of Dessau, had very generously put into our hands the valuable collection of drawings of the solar disk made by him during the course of about forty years, and thus it became an object of importance to us to fix upon some method of testing the value of these drawings, and of extracting from them what information they might contain.