(Ki l PHILOSOPHICAL TKANSACTIONS. [ANNO 1785. 



can have no connection with the nebula, is a total blackness ; and within the open 

 part, towards the north-east, k; a distinct, small, faint nebula, of an extended 

 shape, at a distance from the border of the great one, to which it runs in a pa- 

 rallel direction, resembling the shoals that are seen near the coasts of some 

 islands. 



The Qth is that in the girdle of Andromeda, which is doubtless the nearest of 

 all the great nebulae ; its extent is above a degree and a half in length, and, in 

 even one of the narrowest places, not less than l6' in breadth. The brightest part 

 of it approaches to the resolvable nebulosity, and begins to show a faint red 

 colour; which, from many observations on the colour and magnitude of nebulae, 

 I believe to be an indication that its distance in this coloured part does not ex- 

 ceed 2000 times the distance of Sirius. There is a very considerable, broad, 

 pretty faint, small nebula near it; my sister discovered it August 27, 1783, with 

 a Newtonian 2-feet sweeper. It shows the same faint colour with the great one, 

 and is, no doubt, in the neighbourhood of it. It is not the 32d of the Con- 

 noissance des Temps ; which is a pretty large round nebula, much condensed in 

 the middle, and south following the great one ; but this is about ■§ of a degree 

 north preceding it, in a line parallel to (3 and v Andromedas. 



To these may be added the nebula in Vulpecula : for, though its appearance is 

 not large, it is probably a double stratum of stars of a very great extent, one end 

 of which is turned towards us. That it is thus situated may be surmised from its 

 containing, in different parts, nearly all the 3 nebulosities ; viz. the resolvable, 

 the coloured but irresolvable, and a tincture of the milky kind. Now what great 

 length must be required to produce these effects may easily be conceived when, in 

 all probability, our whole system, of about 800 stars in diameter, if it were seen 

 at such a distance that one end of it might assume the resolvable nebulosity, would 

 not, at the other end, present us with the irresolvable, much less with the 

 colourless and milky sort of nebulosities. 



yj perforated nebula, or ring o/ stars. — Among the curiosities of the heavens 

 should be placed a nebula, that has a regular, concentric, dark spot in the 

 middle, and is probably a ring of stars, It is of an oval shape, the shorter axis 

 being to the longer as about 83 to 100; so that, if the stars form a circle, its 

 inclination to a line drawn from the sun to the centre of this nebula must be 

 about 56 degrees. The light is of the resolvable kind, and in the northern side 

 3 very faint stars may be seen, as also 1 or 2 in the southern part. The ver- 

 tices of the longer axis seem less bright and not so well defined as the rest. 

 There are several small stars very near, but none that seem to belong to it. It 

 is the 57th of the Connoissancc des Temps. Fig. 10 is a representation of it. 



Planetary nebula. — I shall conclude this paper with an account of a few hea- 

 venly bodies, that from their singular appearance leave me almost in doubt v\ here 



