298 Dr. Herschel's Astronomical Observations 
be highly probable, that the appearance of irregular round 
nebulae are owing to so many irregular globular expansions 
of nebulous matter, it will be necessary to direct our attention 
to the cause which has formed this matter into such masse.;. 
To ascribe an highly improbable event to chance is not philo- 
losophical ; especially as a forming cause offers itself to our 
view, when we direct an eye to the globular figure of the 
planets and satellites of the solar system. 
17. Of round Nebulce. 
From what has been said, it appears that the figure of ne- 
bulas is a subject of more interest than mere curiosity. The 
following fifty-seven were observed to be round, and I give 
them here in four assortments.* 
As the title of each sort gives all that is necessary for the 
present purpose relating to the various sizes of round nebulae, 
a description of one of the last will be sufficient. The obser- 
vation of I. 2 6g says, that it is “ A considerably bright round 
nebula of about one minute in diameter/' See fig. 11. 
The arguments which I have given in the foregoing article, 
where only nebulae of an irregular round figure were consi- 
dered, need not be repeated when a regular circular form is 
presented to our view ; for the additional number of nebulae, 
* See three round nebula. III. 381, 51 1, 754. 
Forty-one round nebula of various small sizes. I. 275. II. 54, 218, 223, 225, 329, 
6 59, 760, 803. III. 11, 50, 78, 94, 95, 96, 149, 150, 180, 181, 209, Z21, 222, 295, 
371, 451, 477, 505, 622, 631, 67 1, 684, 7 26, 760, 800, 801, 810, 842, 888, 909, 
946, 971. 
Ten round nebula of various large sizes. I. 7, 124, 252. II. 19, 481, 889. III. 
54’ 77’ U2> 45 2 - 
Three round nebula from 1 to 6' in diameter. I. 269. II. 593. V. 16. 
