22 NOTES BY THE EDITOR 



as they are in nature. The advantages of photography over engraving 

 are considerable, when the naturalist -wishes to represent a body of a very 

 complex structure ; but in another regard it has much more important 

 advantages. When the zoologist draws, he represents only what he sees 

 in his model ; he brings out, as it were, only what goes to confirm the 

 ideas he has formed upon the structure of the body : while photography, 

 bringing out everything, allows every one disposed to dispute the system 

 of the author, liberty to do so, and places in their hands all the elements 

 of the controversy. Another naturalist may even make discoveries upon 

 these faithful images of nature, as he could have done upon nature itself. 



A valuable manual of all the recent processes in photography has re- 

 cently been published in New York, by Mr. Humphrey, the editor of the 

 Daguerrian Journal. 



"Stellar Astronomy continues to manifest a vigor and activity worthy 

 of the lofty interest which attaches to it. Bessel had made a survey of all 

 stars to those of the ninth magnitude inclusive, in a zone lying between 

 45 of north, and 15 of south declination. Argelander has extended 

 this zone from 80 of north to 81 of south declination. It comprises 

 more than 100,000 stars. Last year was published also the long-expected 

 work of Struve, containing a catalogue of stars observed by him at 

 Dorpat, in the years 1822-43. They are principally double and multiple 

 stars, which had been previously micrometrically observed by the same 

 distinguished astronomer. Their number amounts to 2874 ; the epoch of 

 reduction is 1830. The introduction contains the discussion of various 

 important points in stellar astronomy. 



" Notices have been brought before us, from time to time, of the nebulas 

 observed through Lord Rosse's telescope. This noble instrument, so un- 

 rivalled for observations of this kind, continues to be applied to the same 

 purpose, and to add yearly to our knowledge of the remotest regions of 

 space into which the eye of man has been able to penetrate. Almost every 

 new observation appears to confirm the fact of that curious tendency to a 

 spiral arrangement in these nebulous masses of which mention has so fre- 

 quently been made. To those persons, however, who have neither seen the 

 objects themselves, nor careful drawings of them, a mere verbal description 

 must convey very indistinct conceptions of the spiral forms which they 

 assume. 



* ' The refinement of modern methods of astronomical observation has be- 

 come so great, that astronomers appear very generally to think that a 

 higher degree of refinement in the calculations of physical astronomy than 

 has yet been attained is becoming necessary. Mr. Adams has been en- 

 gaged in some important researches of this kind. He has corrected an 

 error in Burckhardt's value of the moon's parallax ; and he has also 



