NATURE 



{June II, 1874 



photography to spectroscopic observations. There are few things 

 so difficult, I tliinl<, as to make a proper spectroscopic observation, 

 while from tlie little experience I have had at present I should 

 think there is nothing more easy than to produce passable spec- 

 troscopic photographs. 

 That, then, was in the year 1862. In the year 1863 we have 



anothei equally distinct advance to chronicle, but this time the 

 Aiork is done in France. M. Ma^cart — a name very well known 

 to physicists— undertook a tremendous work, which he has not 

 yet completed, namely, a complete investigation of the ultr.i 

 violet solar spectrum.* Instead of using a quartz prism, as Dr. 

 Miller had done before him, M. Mascart use; a diffraction 



Fig. 5. — Dr. Miller's arrangements, — 5, slit ; /, quartz lens ; i", camera : /, quartz prism : t, collimator- 



grating, that is to say an instrument by means of which the 1 therefore, you avoid altogether the imperfect transparency of the 

 light is not refracted, as in the case of the prism, but diftVacted glass. Prof. Mascirt has gone on advancing every year, until 

 by an effect of interference of fine lines ruled on glass. M. now he has completed a photographic map, not only of the solar 

 Mascart has shown it to be possible, by means of reflecting light 1 spectrum extending about as fir as the line R., by means of 

 from the first surface of the diffraction gratings, to get light } photography, but he has been able to observe as far as the line 

 diffracted without its going through the glass at all. In this way, ' called T. There I15 finds the solar speatraai ends; but in the 



B q P N Ml 



sl.,l..lJl 



■3JL. 



\.>.X->.X.i.i..>,i:.\..y... 



,!£.i,.x,.i„^„i,.i£,i..x..i,j''.i:, 



Fig. 6,— W.avc-le 



jth solar spectrum showing the lines (from L to R) tlie positions of which have been determined by M.i 

 short the ultra-violet spectrum of the sun is as compared with that of the chemical elements. 



casft of a great many vapours, such, for instance, as that of 

 cadmium and other metals of tlie same nature, he finds he can 

 go on pliotographing very much farther, and has been able to 

 photograph almost as far as the eye can see, that is to say, to a 

 distance, as I have already told you, five or six, or even seven 

 times as far from the line II as H is from A. So that yeu see, 

 thanks to photography, we can now photograph six times more 

 of the spectrum than we can see of it with the eye ordinarily. 

 J. N0RM.\N LOCKYER 



(To be continued.) 



THE CENTRAL PARK OF NEW YORK AND 



MR. XVATERHOUSE H. AW KINS 

 C OME time ago (Nature, vol. vi. p. 70) we copied from 

 *--' the American Naturalist an account of the destrtic- 

 tion "by order of iMr. Henry Hilton " of Mr. Waterhouse 

 Hawkins' restorations of Hadrosaiinis and other extinct 

 animals, in the Central Park of New York. We have 

 lately received some further correspondence on this 

 subject, from which it appears that in April last Mr. 

 Hawkins addressed to the Board of Commissioners of tlie 

 Central Park a memorial, setting forth the manner in 

 which he had been treated, and claiming compensation 

 for his losses. It is not very easy to understand the origin 

 of the affair, which appears to have occurred through some 

 change in the government of the city of New York, pro- 

 duced by the notorious " Ring." But it is quite evident 

 that Mr. Hawkins has the sentiments of all the leading 

 scientific men of the United States in his favour. 



Prof. Henry, of the .Smithsonian Institution, speaks of 

 the destru tion of Mr. H .wknis' models as a "disgrace to 



the country, which nothing can wipe out, sive a renewal 

 of the work on a more liberal scale." Prof. Newbury, and 

 other .fi?r'<?«i'j-, write in a similar strain. There can there- 

 fore, we suppose, be no doubt that Mr. Hawkins will ulti- 

 mately receive ample compensation for the treatment 

 which he has received from Mr. Hilton and his subordi- 

 nates. 



EUCALYPTUS GLOBULUS IN MAURITIUS 



'X'HE subject of the introduction of the Eucalyptus as 

 -^ a sanitary agency in fever-stricken countries has of 

 late been so much talked about that some authoritative 

 preliminary inquirieshavebeen made with the view of plant- 

 ing Eucalyptus ;^lobulits on a large scale in the -Mauritius. 

 From these inquiries, directed chiefly as to the possible suc- 

 cess of the plant in the island, it appears that it does not 

 thrive in any part, and still less in the warmer parts. The 

 tree, moreover, is unsuited to resist the violent winds or 

 hurricanes with which the Mauritius is fo frequently 

 visited. In 1865 twelve plants were planted m the 

 Botanic Gardens at Parapelmousses, and though they 

 were secured to strong stakes, eleven of them were de- 

 stroyed in the hurricane of 186S ; the remaining oiie also 

 was blown over, but met with some support by ialling into 

 the branches of another tree, where it still remains. 



Though it appears at one time thousands of young 

 plants were planted in the lower parts of the island very 

 few at the present time exist ; there are, however, several 



* "Annales scicntifiques da TEcole normalc Supericure.'* Vol. for 1864, 



