C 477 3 
XVIII. Catalogue of 5 00 new Nebula, nebulous Stars, planetary 
Nebula, and Clusters of Stars ; with Remarks on the Con- 
struction of the Heavens. By William Herschel, LL. D . 
F. R. S. 
Head July 1, 1802. 
Since the publication of my former two catalogues of nebulae, 
I have, in the continuation of my telescopic sweeps, met with a 
number of objects that will enrich our natural history, as it 
may be called, of the heavens. A catalogue of them will be 
found at the end of this paper, containing 500 new nebulae, 
nebulous stars, planetary nebulae, and clusters of stars. These 
objects have been arranged in eight classes, in conformity 
with the former catalogues, of which the present one is there- 
fore a regular continuation. This renders it unnecessary to give 
any further explanation, either of the contents of its columns, or 
the abbreviations which have been used in the description of 
the objects. 
It has hitherto been the chief employment of the physical 
astronomer, to search for new celestial objects, whatsoever might. 
be their nature or condition ; but our stock of materials is now 
so increased, that we should begin to arrange them more scien- 
tifically. The classification adopted in my catalogues, is little 
more than an arrangement of the objects for the convenience 
of the observer, and may be compared to the disposition of the 
books in a library, where the different sizes of the volumes is 
MDCCCII, 
