my attention already in the beginning of the year 1774, when viewing it with a Newtonian reflector I made a drawing of it, to which I shall have occasion hereafter to refer: and having from time to time reviewed it with my large instruments, it may easily be supposed that it was the very first object to which, in February 1787, I directed my 40-feet telescope. The superior light of this instrument shewed it of such a magnitude and brilliancy that, judging from these circumstances, we can hardly have a doubt of its being the nearest of all the nebulæ in the heavens, and as such will afford us many valuable informations. I shall however now only notice that I have placed it in the present order because it connects in one object the brightest and faintest of all nebulosities, and thereby enables us to draw several conclusions from its various appearance."[1] By nebulosity or nebulous matter he meant "that substance or rather those substances which give out light, whatsoever may be their nature, or of whatever different powers they may be possessed."[1] From a laborious examination of these vast regions of visible nebulous matter, Herschel found reason to conclude that the power of gravitation was condensing the matter towards one or more centres, which shone with greater brilliance than the rest of the mass. A motion of rotation round an axis would also probably result from innumerable particles pressing towards a centre, and the matter which did not condense into a nucleus—perhaps a star or sun—
