536 BIBLIOGRAPHY OF HERSCHEL'S WRITINGS. 



Herschel, "W.: Synopsis of the Writings of— Continued. 

 A. D. 7ol. P. 



of this instrument, and are already, in some respects, pointed out 



to me by it. 



1784 74 437 By taking more time I sliould undoubtedly be enabled to speak more 



confidently of the interior construction of the heavens and its vari- 

 ous nebulous and sidereal strata, of which this paper can give only a 

 few hints. 



438 As an apology for this prematurity it may be said that the end of all 

 discoveries being communication, we can never be too ready in giv- 

 ing facts and observations, whatever we may be, in reasoning upon 

 them. 



438 Hitherto the sidereal heavens have been represented by the concave 

 surface of a sphere. In future we shall look upon those regions 

 into which we may now penetrate as a naturalist regards a rich ex- 

 tent of ground containing strata variously inclined and directed as 

 well as consisting of very different materials. 



438 Resolution of the milky way. 



439 Number of stars visible in field of the 20-foot telescope. 



440 Examination of Messier's nebulae. 



442-446 New nebulae have been found with the first 20-foot reflector of 12 

 inches aperture; figures of some of these given in Plate XVII. 



442 Arrangement of nebulae and clusters in strata, sometimes of great 



length. 



443 Sun near the centre of the milky way. See Plate XVIII. 



445 Star gauging defined. 



446 Table of results of star gauging from 15^ 01™ to 16^ 37™ R. A. and from 



92° to 94° N. P. D., and ll^^ 16™ to 14^^ 30™ and 78° to 80° N. P. D. 

 448 The solar motion explained by the situation of the sun in the milky 

 way. 



448 Local distribution of nebulae — nebulas are often surrounded by spaces 



vacant of stars. 



449 Strata of Cancer and Coma Berenices described. 



449 Although my single endeavors should not succeed in a work which 

 seems to require the joint effort of every astronomer, yet so much 

 we may venture to hope that by applying ourselves with aU our 

 powers to the improvement of telescopes, which I look upon as yet 

 in their infant state, and turning them with assiduity to the study 

 of the heavens, we shall in time obtain some faint knowledge of, 

 and perhaps be able partly to delineate, the interior construction 

 of the universe. 



With this memoir is a plate of figures of nebulae. Plate XVII, fig. 1, 

 M. 98; 2, M. 53; 3, H., ii, 28 [resolvable]; 4, H., i, 18; 5, H, iii, 15; 

 6, H., iv, 5; 7, H, iv, 2; 8, H, iv, 3; 9, 10; 11, H, i, 13; 12, 13, 14, 15T 



Also Plate XVIII, construction of the heavens — cloven disk. 



1785 75 40 Catalogue of Double Stars. By William Herschel, Esq., F. R. S. 



Read December 9, 1784. 

 40 Introductory remarks. The great use of double stars having already 

 been pointed out in a former paper on the Parallax of the Fixed 

 Stars, and in a latter one on the Motion of the Solar System, I have 

 now drawn up a second collection of 434 more, which I have found 

 out since the first was delivered. 

 The method of classing them is in every respect the same as that 

 which is used in the first collection. 



