relating to the Construction of the Heavens. 295 
I. 134 is “ A considerably bright nebula, 7 or 8 minutes long 
“ and about 3' broad.” 
The considerable breadth of these nebulae, although chiefly 
extended in length, proves that two of the dimensions of the 
nebulous matter, namely, the breadth and depth, are probably 
not very different ; for if the depth, which is the dimension we 
do not see, should be equal to the length, the chance of its 
being out of sight is not sufficiently probable to happen very 
frequently. It is therefore to be supposed that the extension 
in length is really the greatest ; for as we actually see it under 
this form, we are assured that it is at least as long as it ap- 
pears, whereas one of the other dimensions, if not both, 
must certainly be less than the length. This kind of expan- 
sion admits of the utmost variety of lengthened form and 
position ; and from the great number of nebulae to which I 
have referred, the existence of such nebulosities is fairly to be 
deduced. 
15. Of Nebulce that are of an irregular Figure . 
Among the various figures that may be seen in nebulae we 
have a great many that are of an irregular appearance ; I have 
divided the following ninety-three into two assortments.* 
I. 6 1 is “ A very bright small nebula north-following a 
* See sixty-one irregular nebula of various small sizes. I. 6 i, 284. II. 185, 242^ 
259, 274, 281, 306, 339, 415, 445, 586, 597, 601, 605, 647, 744, 761, 834, 886, 893, 
907. III. 12, S3, 191, 259, 273, 287, 301, 310, 456, 465, 485, 486, 493, 495, 533, 
535, 537, 555’ 5 8i > 5 8z > 6 o 5> 642, 663, 675, 699, 701, 724, 735, 795, 817, 834, 
847, 851, 868, 879. 893, 963, 976, 977. 
Thirty-two irregular nebula of various large sizes. I. 138, 246, 248, 282. II. 
43, 81, 149, 289, 346, 349, 360, 421, 467, 468, 495, 587, 651, 681, 711, 749, 75 6, 
804, 877. III. 137, 257, 274, 463, 683, 695, 765, 91 1, 938. 
