Nov. 26, 1885] 



NA TURE 



schools are often employed on fine days in planting out young 

 trees. Thus during last summer some thousand acres have been 

 planted in a single parish alone. Of late years private indi- 

 viduals too have done a great deal to retrieve the deforestation 

 which has been going on by planting new trees. In one single 

 parish in Norway, for instance, a proprietor has planted on 

 waste land no less than a quarter of a million of spruce, fir, and 

 larch trees, all obtained from the Government nursery. The 

 price of the young plants is one farthing, and only 10 per cent, 

 of the plants die. Afrer thirty years each is valued at 70'. in the 

 ground. These are of course valuations in a country where both 

 labour and timber are cheap. 



We learn that Dr. J. G. Garson has just been elected a Cor. 

 responding Member of the Anthropological Society of Paris. 



A.S a memorial to the late Sir Titus Salt, and in recognition 

 of his benefactions to Saltaire, the Governors of the Salt Schools 

 have decided to build a new Science and Art School, costing 

 about 6000/. The building will be completely finished by May 

 15, on which day will be opened an important exhibition on the 

 lines of the late International Inventions Exhibition. For this 

 purpose the present buildings and a field of six acres will be 

 utilised. The arrangement and supervision of the lighting and 

 other electrical work have been intrusted to Messis. Woodhouse 

 and Rawson, of London. 



In the last number of the Bulletin of the American Geo- 

 graphical Society, Mr. Ernest Ingersoll publishes a paper on 

 the manner in which the settlement of North America has 

 affected its wild animals. He takes in succession the customary 

 divisions of animal life— mammals, birds, reptiles, fishes, and 

 the almost counties^ invertebrates, and shows how far these 

 prevailed geographically in historical times, and how they have 

 now either disappeared altogether, or been driven northwards 

 into the Canadian forests, or, in the case of fish, away from the 

 coasts. Mr. Ingersoll thus ranges over the whole animal 

 kingdom , and in every department he has to record destruction — 

 in many cases wanton and useless — and disappearance. It is a 

 most instructive and interi;stiDg paper. 



The Sanitary Institute of Great Britain has just completed 

 the preparation of a volume which will be of great interest to 

 the statistical world, containing selections from the reports and 

 writings of the late Dr. W. Farr. The selection of the papers 

 and reports and the editing of this work have been undertaken 

 by Mr. Noel A. Humphreys, of the Registrar- General's Office. 

 The volume consists of 550 pages and is divided into six parts : 

 (l) population, (2) marriage, (3) births, (4) deaths, (5) life 

 tables, (6) miscellaneous. It has long been the source of much 

 regret among students of vital statistics, and others practically 

 interested in that branch of sanitary science, that from the form 

 and manner of the publication of Dr. Farr's valuable papers on 

 statistics they have not been generally available, being scattered 

 over a long series of Blue-Books and other Reijorts. The 

 object of the Institute in publishing the selection is to give those 

 interested in the subject a ready means of studying the valuable 

 writings and tables of that eminent statistician. 



The additions to the Zoological Society's Gardens during the 

 past week include a Rhesus Monkey {Macacus rhesus 9 ) from 

 India, presented by Mrs. Berry ; two Black-eared Marmosets 

 {Hapalc pcnicillala) from South-East Brazil, presented by Miss 

 L. M. Graham ; two Emus {Droiiiaiis nova-hollandicT) from 

 Australia, presented by Lord Northesk ; an Emu {Dromaus 

 nova-hol landiie) from Australia, presented by Mr. A. Garrett 

 Smith ; a Cuvier's Podargus [Podargus cuvieri) from Australia, 

 presented by Mr. Cromwell Collins ; a Tawny Owl [Syrnium 

 aluco), British, presented by Mr. Phillips ; an Anaconda 

 (Eunectes murinus) from Demerara, presented by Mr. G. H. 



Hawtayne, C.M.Z.S. ; a Robben Island Snake (Corondla 

 p/iocarum), a Hoary Snake (Coronella eana) from South Africa, 

 presented by the Rev. G. H. R. Fisk, C.M.Z.S. 



OUR ASTRONOMICAL COLUMN 

 The French Photographs of the Transit of Venus. — 

 The measurement of the 700 photographs obtained at the various 

 French stations during the transit of Venus, 1882, is about to 

 be commenced. An office has been organised for the purpose, 

 the necessary credit has been granted, and a measuring instru- 

 ment, belonging to the Meudon Observatory and lent by M. 

 Janssen, has been supplied. This will be replaced in January 

 next by a smaller one by the same makers, MM. Brunner, 

 Freres. The measurements, it is expected, will be completed 

 in fifteen months. 



The Absorption-Spectrum of Oxygen. — M. Janssen, 

 continuing at the Meudon Observatory his important and diffi- 

 cult researches on the spectra of the gaseous constituents of the 

 terrestrial atmosphere, has recently given {Coiiiptes rendus, vol. 

 ci. No. 14) a brief notice of the results he has obtained. The 

 spectrum of an intensely brilliant light is viewed through a 

 tube 60 m. in length containing oxygen, the pressure of the gas 

 being constantly increased up to a pressure of 27 atmospheres. 

 With the increase of pressure, dark lines or groups of lines 

 appear. The first to appear are those groups in the red, which 

 M. Egoroft", who was the first to observe them, considered to be 

 the A and B of the solar spectrum. With higher pressures, and 

 a more brilliant source of light, lines are suspected between A 

 and B and between B and C. Lastly, with the greatest pressures 

 three dark bands appear ; one near o, one near D, but more 

 refrangible, and one in the blue. The solar spectrum does not 

 show any similar bands, which, therefore, can scarcely be 

 ascribed to oxygen in the state in which it exists in our atmo- 

 sphere. 



The Apparent Enlargement of Celestial Objects 

 near the Horizon. — M. Paul Stroobant has recently devoted 

 a considerable amount of care to examining the cause of this 

 well-known phenomenon. His experiences lead him to reject 

 the theories most commonly received, that the appearance is due 

 either to comparison with terrestrial objects, or to the "flattened 

 arch " shape ascribed to the celestial vault. E.vperiments made 

 with pairs of electric sparks in a lofty hall, showed that if the 

 two sparks overhead were 100 mm. apart, the pair on a level 

 with the eye, and equally distant from the observer, needed only 

 to be 81-5 mm. apart to seem separated to a similar extent. 

 Comparisons of various pairs of stars gave a similar result, and 

 the following formula was found to represent the apparent size, 

 G, of a celestial object, at any given altitude, H, when the size 

 on the horizon was taken as ICX) : — 



G = 100- 19 sin H. 

 Beside this relation, depending evidently on some physiological 

 effect connected with the position of the head, M. Stroobant 

 found that an increase in the brightness of an object caused an 

 apparent diminution in its size, and ■vice versd. The great 

 apparent size of the moon at rising was therefore, he considered, 

 largely due to its comparative faintness when near the horizon. 



Nova Andromed.-e and its Relation to the Great 

 Nebula. — There seems to be considerable difference of opinion 

 as to whether the new star is to be regarded as having a real 

 physical connection with the nebula, or as being connected with 

 it in appearance only. M. Trouvelot {Comptes rendus, vol. ci. 

 No. 17) ably pleads for the latter view. Comparing the present 

 aspect of the nebula with the chart he made of it in 1874, he 

 finds two new stars in the central district, one being the present 

 Nffva, the other a star of the 13th or 14th magnitude, which pre- 

 cedes it by about 20s. But he believes that the nebula itself 

 has undergone no change during the appearance of the Nova, 

 the impressions to the contrary being, he thinks, due to the superior 

 light of the star having overpowered for a time the suiTounding 

 portions of the nebula ; so that the arguments founded upon 

 these supposed or apparent changes lose their force. The 1874 

 chart shows some 1283 little stars, which by their feebleness 

 and crowding present the characteristic features of the Milky 

 Way, which indeed appears to extend somewhat beyond the 

 nebula ; and these stars also appear to become less and less 

 numerous the farther the observer travels from the Milky Way. 



