relating to the Construction of the Heavens. 279 
“ abruptly to the north and is diffused to the south.” See 
fig. 2. 
No. 42 of the Connoissance is the great nebula in the con- 
stellation of Orion discovered by Huyghens. This highly 
interesting object engaged my attention already in the begin- 
ning 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 , 1 directed 
my forty 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 nebulas 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 nebu- 
losities, and thereby enables us to draw several conclusions 
from its various appearance. 
The first is that the extensive diffused nebulosities contained 
in the objects of the preceding articles are of the same nature 
with the nebulosity in this great nebula ; for when we pursue 
it in its extensive course it assumes precisely the same appear- 
ance as the before-mentioned diffused nebulosities. 
The second consequence we may draw 7 from the circum- 
stance of its containing both the brightest and faintest nebu- 
losity joined in one object is a confirmation of an opinion 
already conceived in the second article, namely, that the range 
of the visibility of nebulous matter is what may be called very 
limited. The depth of the nebula may undoubtedly be ex- 
