October 20, 1898] 



NATURE 



605 



is an important phenomenon in that of x-rays ; experiments in- 

 dicate that these rays are evidence of an electromagnetic dis- 

 turbance, which therefore travels with the velocity of light, and 

 is accompanied by molecular excitation. The mechanism of the 

 production of x-rays appears to be a setting-up of electrostatic 

 lines of induction, and a production of an electromagnetic wave 

 or impulse; the stress in the medium reduces its resistance, and 

 the -v- radiations become less and less energetic after a certain 

 interval the longer the Crookes' tube is excited. The behaviour 

 of rarefied media to powerful electric stress is analogous to that 

 of elastic solids to mechanical stresses ; a so-called vacuum, 

 which acts as an insulator for electromotive forces giving a spark 

 of 8 inches in air (about 200,000 volts), breaks down under 

 3,000,000 volts. A single discharge with this voltage 

 through highly rarefied media produces x-rays powerful 

 enough to give a photograph of the bones of the hand in one- 

 millionth of a second. During the discharge the apparent 

 resistance of the medium is only a few ohms. In this case the 

 medium seems completely to lose its elasticity, so to speak, and 

 is ruptured, and the elastic solid analogy thus seems to elucidate 

 the question of the electrical conductivity of the ether. 



Mr. D. E. Hutchins, Conservator of Forests at the Cape, 

 recently read before the Cape Town Philosophical Society a 

 paper showing the need and value of extending the area in the 

 Colony at present under forest. Cape Colony stands far 

 below other countries in its proportion of forest, though the 

 climate of the country is such that it ought to have a percentage 

 under forest at least equal to Germany. The following table 

 shows the area under forest in the Colony compared with that 

 in some other countries : — 



Percentage 

 Area under under 



Countries. forest in forest of 



acres. total area 



of country. 



Russia in Europe 527,427,000 ... 42 



Sweden 42,366,000 ... 42 



Austria 46,856,000 ... 31 



Germany ... 34,350,000 ... 26 



Norway 18,920,000 ... 25 



India ... 140,000,000 ... 25 



France 20,750,000 ... 16 



Portugal 1,666,000 ... 5 



Great Britain and Ireland ... 2,790,000 ... 4 

 Cape Colony 353,280 ... 0*29 



Mr. Hutchins suggests that plantations should be formed in 

 districts within minimum rainfall limits of 15 or 20 inches per 

 annum. The argument which will perhaps appeal most forcibly 

 to Cape agriculturists is that while the total value of the fruit 

 produced in Cape Colony is 100,000/., no less than 269,349/. 

 have been paid for wood imported into the Colony during the 

 last two years, nearly the whole of which would be produced in 

 national forests covering an area of about 50,000 acres. That 

 forests can thrive where agriculture is difficult or impossible, is 

 shown by the steep richly- wooded slopes of the lofty Amatolas, 

 the .similarly beautiful forest with its gigantic yellow-wood trees 

 in the barren Knysna country, and, perhaps most striking of 

 all, the cedar trees of Clanwilliam, growing on the absolutely 

 bare rocks of the stupendous Cedarberg Range ; while at 

 Genadendal an introduced tree, the cluster pine, hardier than 

 any of the indigenous trees, is spreading itself self-sown up the 

 rocky mountain-side, in spite of fires, drought, hot winds and 

 climatic vicissitudes, that are too often the despair of ihe 

 agriculturist. 



A PAPER on the "Wanton Mutilation of Animals," con- 

 tributed by Dr. George Fleming to the Nineteenth Century for 

 March 1895, has l)een issued in separate form by the Royal 

 Society for the Prevention of Cruelty to Animals. The paper 

 shows that many mutilations of this kind can boast of a vener- 1 



able antiquity, and are practised in many countries. The practice 

 of removing a portion of the tails of certain breeds of dogs 

 appears to have been instituted as a means for the prevention of 

 rabies, the belief being that the sinew which followed the piece 

 bitten off was a worm which produced madness. " Worming," 

 which was performed upon dogs for the same purpose, consisted 

 in the excision of the fraenum of the dog's tongue, under the 

 impression that it had something to do with madness. Ear- 

 cropping of dogs has been carried on for two or three centuries. 

 Horses are subjected to tail-docking, ear-cropping, nostril-slitting, 

 and other unnecessary mutilations. The fashion of mutilating 

 horses appears to have prevailed at a very early date in England, 

 and may have been introduced from Germany or Scandinavia. 

 Dr. Fleming's descriptions will assist in suppressing these cruel 

 and useless practices. 



Messrs. Williams and Norgate's Book Circular for 

 October, and their latest list of second-hand books (No. 10), 

 contain the titles of a number of volumes on scientific subjects. 

 — A more elaborate catalogue, occupying 686 pp., is the new 

 volume of " Naturae Novitates " just issued by Messrs. R. 

 Friedlander and Son, Berlin, This publication not only con- 

 tains classified lists of books in many languages on all branches 

 of science, but the works named in it are indexed according to 

 subjects and authors. 



The following official publications from our foreign posses- 

 sions have reached us: — The Central Africa British Gazette 

 (published at Zomba) for July 9, containing an interesting 

 report on the cultivation of coffee, compiled by the Commissioner 

 of Agriculture to the Hawaian Government ; Report on the 

 Botanic Gardens and Domains, New South Wales, for the year 

 1897, by the Director, Mr. J. H. Maiden ; Annual Report of 

 the Royal Botanic Garden, Calcutta, for the year 1897-98, by 

 the Superintendent, Dr. D. Prain, chiefly occupied by a list of 

 exchanges; Bulletin (No. 15) of Miscellaneous Information 

 from the Royal Botanic Gardens, Trinidad, edited by the Super- 

 intendent, Mr. J. H. Hart, and consisting of a conspectus of 

 the genera of Ferns and Fern-allies of the Colony, and a mono- 

 graph of the Cyatheaceiie, comprising the genera Alsophila (14 

 sp.), Hemitelia (15 sp.), and Cyathea (25 sp.) ; Circular, Nos. 

 4-7, of the Royal Botanic Gardens, Ceylon, issued by the 

 Director, Mr. J. C. Willis, in which the extension of the rubber 

 cultivation in the island is advocated, especially that of the Para 

 rubber, Hevea brasiliensis, which is stated to be well suited to 

 the climate of the low country in the south-west of Ceylon. 



The additions to the Zoological Society's Gardens during the 

 past week include a Tantalus Monkey (Cercopitheciis tan- 

 talus, i ) from Lagos, presented by Mr. Arthur T. Warren ; 

 a Macaque Monkey (Macacus cynomolgus) from India, pre- 

 sented by Mr H. W. Mote ; two American Flying Squirrels 

 (Sciuropterus volucella) from North America, presented by 

 Mrs. Nias ; a Bengalese Cat {Felis bengalensis) from the East 

 Indies, presented by Mr. David J. Munro ; a Ruddy Ichneumon 

 {Ilerpestes sinithi) from India, presented by Mr. J. Lyons ; a 

 Black-headed Lemur {Lemur brunneus) from Madagascar, 

 deposited; an Eland (Orias canna, 6), bred in France 

 purchased. 



OUR ASTRONOMICAL COLUMN. 



The Andromeda Nebula.— In this column (September 22, 

 p. 515) we have previously referred to the telegram which in- 

 formed us that M. Seraphimoff had discovered, near the centre 

 of the nebula of Andromeda, a stellar-like condensation. 

 Writing to the Astr. Nachr. (No. 3523), he states- that the 

 central condensation is no nebulous nucleus, but is quite a dis- 

 tinct star of magnitude lo-ii. Measurements with a star of 

 magnitude 1 1 in the neighbourhood showed that the observed 



NO. 



1512, VOL. 58] 



