late Professor of Practical Astronomy in Glasgow. 13 



amined, prove in the clearest manner that the spots themselves 

 are depressions in the luminous matter of the sun, and lead to 

 many new and interesting ideas concerniTig the nature and con- 

 stitution of that stupendous body. 



But though he was the first astronomer to whose lot it fell 

 to remark these phenomena of the solar spots which have been 

 just now described, and to draw such important conclusions from 

 them, it appears that the celebrated Mr Flamstead, so far back 

 as the year 1676, had very nearly anticipated this discovery. 

 For, one day when observing a spot of considerable size near 

 the sun's limb, he actually beheld this appearance of the dusky 

 zone which belongs to the nucleus, finding it almost wholly 

 deficient on that side which respected the centre of the disk ; 

 and this, too, when the distance of the spot from the limb cor- 

 responded very nearly with that which Dr Wilson found to be 

 so constant in his observations. Mr Flamstead was then, in- 

 deed, viewing his spot in peculiar circumstances, and the most 

 favourable of all to perfect vision of the sun, as, by the inter- 

 vention of a mist, he was enabled to use his telescope without 

 the help of tinged glass put before his eye. The following is 

 his account of this remarkable observation, in which, by the 

 word macula, Mr Flamstead evidently means the nucleus of 

 the spot, and by nubecula the dusky zone which surrounds it. 



" 1676, Nov. 9. Deinde densi adeovapores excepere solem, 

 ut per ipsos licuit ilium nudis oculis intueri. Adhibito turn 

 longiore tubo absque vitro rubro, (quo oculum adversus ejus 

 splendorem munire soleo) maculum contemplatus sum : dis- 

 tincta valde videbatur, ejusque figurae quae in schemate adpin- 

 gitur : ' Nubecula ipsi circumducta elliptica omnino ; sed, 

 quod vald^ miratus sum, admodum dilatata a parte limbum 

 respiciente ; ab altera vero versus centrum, maculae fere cohae- 

 rere videbatur.** " 



" Observavi dein maculae a limbo proximo distantium 1' 

 13'/."" — Hist. Ccelest. Flamsteedii, vol. prim. p. 363. 



When Dr Wilson saw the great spot on the 23d November 

 1769, it had nearly the same situation upon the disk, and the 

 same aspect as the one here described. But, at that time, 

 like Mr Fkmstead, he had no conception of what was signified 

 by such an appearance. It was not till next day, after remark- 



