relating to the Construction of the Heavens. 305 
II. 828 is “ A pretty bright small nebula, very gradually 
much brighter in the middle/' 
I. 101 is “ A considerably bright pretty large nebula, ex- 
w tended in the meridional direction, about 4/ or 5' long ; much 
brighter in the middle/' In the 40 feet telescope I saw the 
very gradual increase of brightness towards the middle of its 
length ; a longer extent of the nebula was also visible,, 
Fig. 19. 
I. 219 is “ A very bright considerably large nebula of an 
“ irregular figure, very gradually much brighter in the mid- 
e * die." Fig. 20. 
I. 63 is “ A bright round nebula of about one minute in 
“ diameter ; it is much brighter in the middle, and very faint 
91 towards the border/' Fig. 21. 
The greater difference between the comparative brightness 
of the center, and the outward parts of these nebulae, may 
certainly be ascribed to the same causes that have been consi- 
dered in the two foregoing articles ; but in the present case, 
and taking into the account that this is already a third step of 
condensation from a little brighter to brighter ; then, to much 
Nineteen nebulae of an irregular figure, gradually much brighter in the middle . 
1 . 10, 26, 59, 66, 109, no, 114, 115, ng, 235, 237, 276. II. 2,20, 438,503, 734, 
827. III. 299. 
One hundred and four round or nearly round nebulce, gradually much brighter in 
the middle. I. 8, 16, 21, 30, 42, 63, 65, 67, 68, 74, 79, 83, 87, 88, 100, 102, 105, 
ill, 112, 118, 129, 135, 136, 142, 144, 147, 150, 158, 159, 166, 171, 175, 182, 
185,216,218,221,232,238,244,257,260265,273, 278. II. 5, 11,38,69,98, 
148, 230, 236, 245, 250, 257, 269, 270, 277, 288, 292, 301, 303, 309, 311, 328, 
418,420,446, 462, 466, 556, 561, 564, 575, 598, 632, 644. 645, 660, 666, 695, 
707, 728, 738, 757, 767, 774, 782, 816, 823, 839, 854, 874. III. 250, 284, 512, 
531, 624, 744, 859, S78. Connoiss. 59, 96. 
mdcccxi. R r 
