October 9, 1890] 



NA TURE 



571 



neighbouring street gave it vibrations, which by reflection 

 were doubled in amount. The reflector was therefore 

 abandoned, and Rutherford resolved to have an object- 

 glass made of the same size as that formerly used by him, 

 but specially corrected for photographic rays. With the 

 completion of this instrument Rutherford's best results 

 began. In March 1866, some remarkably fine negatives 

 were obtained with exposures from two to three seconds 

 three days after the first quarter, and one-quarter of a 

 second for the full moon. The publication of enlarge- 

 ments from these negatives, having a diameter of twenty- 

 one inches, was much appreciated by astronomers and 

 others interested in lunar photography. 



No man has done more in the furtherance of celestial 

 photography than Dr. Henry Draper, the son of the 

 renowned physicist to whom reference has already been 

 made. After a brilliant scholastic career he was asso- 

 ciated with his father in many important researches. A 

 journey to the British Isles in 1857 gave Dr. Draper the 

 opportunity of visiting Lord Rosse's observatory at 

 Parsonstown. He was so struck with the power of 

 the great reflecting telescope, that on returning to 

 America in 1858 he began the working of a similar 

 speculum having a diameter of 15 inches. This was 

 afterwards discarded, and a silvered glass Newtonian 

 reflector, having a diameter of 15^ inches, was con- 

 structed, and adapted for celestial photography. Detailed 

 descriptions of the construction and testing of the mirror, 

 the method of silvering, and the manner in which it is 

 mounted, are embodied in a memoir by Dr. Draper " On 

 the construction and use of a silvered glass telescope, 

 I5i inches in aperture, and its use in celestial photo- 

 graphy " (" Smithsonian Contributions to Knowledge," 

 vol. xiv. p. 52, 1864). Instead of driving the telescope 

 in the usual way by means of a clock, Dr. Draper used 

 a sliding plate holder, driven by a " clepsydra " specially 

 devised for the purpose. Some perfectly defined nega- 

 tives were obtained in 1863, about \\ inches in diameter ; 

 many of them were enlarged to 2 feet, and from one a 

 magnificent picture was made in which the lunar disc 

 had a diameter of 50 inches. The beauty of the copies 

 was probably due to some extent to the fact that a 

 concave mirror was used instead of a combination of 

 lenses in the process of enlarging. 



From the time when Dr. Henry Draper produced his 

 best results until last year very little remarkable work had 

 been done in lunar photography. In 1866, Mr. A. Brothers 

 took several good negatives \\ of an inch in diameter 

 in the first focus of a 5-inch refractor, and by the insertion 

 of a Barlow lens he increased the size of the image to 

 \\ inches. Enlargements from these negatives were dis- 

 tributed to many astronomers, and evidence of their 

 excellency is afforded by the circumstance that they were 

 mistaken for some of Rutherford's productions by the 

 editor of a scientific journal, and commented upon as 

 such. Mr. Brothers gave a long account of the develop- 

 ment of celestial photography in the paper in which his 

 method of work was described (Proceedings of the 

 Literary and Philosophical Society of Manchester, vol. v. 

 p. 68, 1865-66.) 



In 1872, Mr. Ellery, the Director of Melbourne Obser- 

 vatory, presented some remarkably sharp lunar photo- 

 graphs to the Royal Astronomical Society, that he had 

 obtained by means of the great reflector {^Monthly 

 Notices R.A.S., vol. xxxiii. p. 219, 1873.) 



Amongst other lunar photographs possessed by the Royal 

 Astronomical Society are two taken by Dr. Gould at 

 Cordoba Observatory in 1875-76, in each of which the 

 moon has a diameter of nearly 20 inches. A photograph 

 taken in 1877 by Prof. Pritchard at Oxford, with the 

 reflector used by De La Rue, and some taken in 1880 by 

 Mr. Common with his three foot reflector, also figure in 

 the above collection as remarkable works of art having 

 an important scientific signification. 



NO. 1093, VOL. 42] 



In a recently published paper on "Astronomical Photo- 

 graphy at the Lick Observatory" ("Publications of the 

 Astronomical Society of the Pacific," vol. ii.. No. 9), 

 Prof. Holden gives a detailed account of the photographic 

 apparatus of the great equatorial, and the work done 

 with it. The image of the moon in the first focus of this 

 instrument is nearly five and a quarter inches in diameter, 

 and the negatives bear easily an enlargement of 570 

 diameters, and even double this amount. In the pro- 

 duction of these negatives the aperture of the object-glass 

 was reduced to 12 inches. From an examination of 

 the best pictures yet taken at the Lick Observatory, 

 Prof. Holden finds that parallel walls on the moon whose 

 tops are no more than 200 yards or so in width, and 

 which are not more than 1000 or 1200 yards apart, are 

 plainly visible. A series of copies from the negatives 

 obtained at Lick observatory has been published. 



Some photographs of the moon taken in March last, 

 by the Brothers Henry, at Paris Observatory, appear to 

 eclipse all previous ones. The instrument used was 

 the 13-inch photographic equatorial, and an examina- 

 tion of the plate which accompanies this note will show 

 that real progress has been made. The superiority of 

 the results is due not only to the perfection of the object- 

 glass, but to the use of a secondary magnifier, by means 

 of which the size of the image at the first focus was 

 increased fifteen times. It is manifest that this method 

 of direct enlargement possesses many advantages over 

 that ordinarily used, and its further development will be 

 awaited with considerable interest. 



There is no doubt that enlarged photographs of our 

 satellite are capable of affording more information regard- 

 ing its surface than can be gained by years of diligent 

 observation, whilst their multiplication at different epochs 

 will enable selenographers to readily detect changes of a 

 comparatively minute character. The study of the lunar 

 surface has always excited interest. Hence the con- 

 tribution to knowledge afforded by the photographs taken 

 by MM. Paul and Prosper Henry will not lack the 

 appreciation it fully deserves. 



Richard A. Gregory. 



COMPA RA TI VE PA LA TAB I LIT Y OF 

 INSECTS, &^c. 



T N the course of last autumn and the present summer 

 ■*■ we made a series of experiments bearing upon the 

 relative palatability of insects, &c., ; the animals chiefly 

 experimented on being domestic mice, common toads, 

 and a common Mynah (Acridotheres tristis). We 

 obtained the following results. 



Among beetles, Carabus violaceus, which emits a very 

 strong, unpleasant-smelling fluid, was once eaten by the 

 toads, and twice by the mice. As a rule, however, it 

 seemed too large and strong for either. The Mynah, 

 also, was not very fond of it. 



Torostichiis niger, and the nearly-allied red-legged 

 species, which also emit strong-smelling fluid, were 

 readily taken by all the animals under observation : 

 though they sometimes caused the mice a little trouble. 



The small copper-coloured ground-beetles were eaten 

 readily by the Mynah and toads, but in every case 

 refused by the mice. 



Melolontha vulgaris was liked by the mice and toads. 

 We did not offer it to the Mynah. 



Coccinella bipunctata was invariably licked and refused 

 by the mice, even when hungry. The toads took it 

 readily. We did not offer it to the Mynah. 



Ocypus olens, the " devil's coach horse," was taken 

 without hesitation by the toads, even in its defiant atti- 

 tude, with the head and abdomen erected. On one or 

 two occasions, however, it was immediately ejected. This 

 has also happened with Torostichus niger, and appears 



