320 Dr. Herschel’s Astronomical Observations 
round ones shew a general approach to the oval form ; now 
these figures are all favourable to a surmise, that a rotatory 
motion may often take place even before the nucleus of a 
nebula can have arrived to a state of consolidation. An objec- 
tion, that this remarkable form of planetary nebulae may be 
owing to chance, will hardly deserve to be mentioned, be- 
cause the improbability of such a supposition must exclude it 
from all claim to refutation. 
31. Of the Distance of the JV'ebula in the Constellation of Orion. 
In my 3d article I concluded, from the appearance of the 
great nebula in Orion, that the range of the visibility of the 
diffused nebulous matter cannot be great, because we may 
there see in one and the same object, both the brightest and 
faintest appearance of nebulosities that can be seen any where. 
It will therefore be a case of some interest, if we can form any 
conception of the place among the fixed stars to which we 
ought to refer the situation of this nebula ; and this I believe 
my observation of it will enable us to determine pretty nearly. 
In the year 1774, the 4th of March, I observed the nebulous 
star, which is the 43d of the Connoissance des Temps, and is 
not many minutes north of the great nebula ; but at the same 
time I also took notice of two similar, but much smaller ne- 
bulous stars ; one on each side of the large one, and at nearly 
equal distances from it. Fig. 37 is a copy of a drawing which 
was made at the time of observation. 
In 1783 , 1 examined the nebulous star, and found it to be 
faintly surrounded with a circular glory of whitish nebulosity, 
faintly joining to the great nebula. 
