€pt. 2 1, 1876] 



NATURE 



465 



iteinational Charts of General Myer, of the United States, will 

 % of the very greatest value. 



Ix a recent rmxcCotx oi Pogqendorff^ s Annalen, Dr. G. Berthold 

 akes an interesting contribution to the history of the radio- 

 eter. It appears that in a paper entitled "Eclaircissement sur 



traite physique et historique de I'aurore boreale," published in 

 le Meinoirs of the Paris Academy for 1747, M. Mairan gives 



description of a light mill. This was a horizontal wheel of 

 on about 3 inches in diameter, having ^six radii ; at the end 

 ■ each radius was a small oblique vane. The axis of the wheel 

 as held by its upper point to the end of a magnetic bar. The 

 eight was only thirty grains. Light was concentrated on it 

 ith a lens. "Nothing could be more mobile," says M. Mairan, 

 than this wheel ; but at the same time nothing is less certain 

 an the induction one might wish to draw from it in favour of 

 1 impulsion by the rays. The machine turns now in one direc- 

 Dn, now in the other, according as you bring one of its vanes 

 ore or less near to the bars, within, or beyond the latter. It 



necessary to conclude that the luminous rays attract and repel 

 ; different points of the cone which is formed by the lens, but 

 le explosion of a mass of air suddenly and unequally heated 

 mnd the vane where the focus is applied, appears to me to give 



sufficient reason for these effects. The perpetual obstacle of 

 le air naturally suggested to me to make one of these experi- 

 lents in vacuo, but I avow that after having reflected a little on 

 hat might be the result, I have not thought it worth while 

 .king the trouble." The reasons which thus unfortunately 

 revented M. Mairan from repeating his experiments in vacuo 

 ere, (i) the difficulty of producing a sufficient vacuum ; (2) the 

 lea, that besides the atmospheric air there was another fluid, 

 hich would penetrate the glass and make the experiment doubt- 

 il ; (3) through action of the burning-glass vapours would rise 

 om the body m vacuo, which would, by their impulsion, set it 

 motion. Dr. Berthold further notices an observation by 

 [icliell in Priestley's "History of Optics ;" a piece of piano 

 ring, 10 in. long, having a square copper plate at one end, and 



grain of shot at the other, was pivoted in a case having its 

 3ver and one side of glass. Solar rays directed from a concave 

 lirror on the copper plate produced repulsion. Priestly con- 

 dered that this motion must not be attributed to impact of the 

 ght rays. 



The French Journal Official publishes a letter from Shanghai 

 lating that a Chinese Polytechnic Institution, supported by 

 rivate contributions, has been opened there. 



Petermann's Mittheilungen for September contains soma 

 apers of great interest. Dr. Hermann Wagner, of Konigsberg, 

 ontnbutes a careful and detailed resume of the most recent 

 rustworthy contributions to a knowledge of the Bolivian littoral, 

 :s physical features, products, and people, accompanied by a 

 lap. Oscar Loew gives the results of Lieut. Wheeler's expedi- 

 lon in California, Nevada, and Arizona for the year 1875, the 

 esults being embodied in a map by Dr. Petermann. Lieut. 

 A^eyprecht's " Pictures from the High North " are continued, 

 he present instalment giving an interesting account of the be- 

 laviour of the sailors of the expedition in the ice. The Brazilian 

 ;n"ineer, Maximilian Emerich, describes the various projects 

 hat have been proposed for a South American Pacific railway, 

 md Dr. Mupperg, of Venice, contributes a picturesque paper on 

 he German element, which is very strong, in Italy, especially in 

 iouth TyroL 



A HURRICANE burst over St. Thomas and St. Croix on the 

 light of the I2th inst. The damage done was not extensive. 

 Raia fell in torrents the whole time. 



Snow has been observed not only in Scotland on the Gram- 

 Dians, but on the Obseivatory of Puy-de-D6me, on the I3th 



instant, and on the Alps round St. Jeanne, Maurienne, and 

 other places, about the same time. 



Her Majesty has directed letters patent to be passed under 

 the Great Seal declaring that the degrees of Bachelor and 

 Master ia Arts, and Bachelor and Doctor in Law, Medicine, and 

 Music, hereafter to be granted or conferred by the University of 

 New Zealand, shall be recognised as academic distinctions and 

 rewards of merit, and be entitled to rank, precedence, and con- 

 sideration in the United Kingdom, and in the colonies and pos- 

 sessions of the crown throughout the world, as fully as if the 

 said degrees had been granted by any university of the said 

 United Kingdom. 



The Dutch Government has ordered from the French Inter- 

 national Metric Commission, a copy of the standard^metre, to be 

 executed at its own expense. The same thing has been done 

 already for the English Government. 



On Oct. I the first number of The Sunday Review will be 

 published by Triibner and Co. It will be a shilling quarterly 

 magazine, the organ of the Sunday Society, whose object, our 

 readers know, is to obtain the opening of museums, art galleries, 

 libraries, aquariums, and gardens on Sundays. 



Part I., Vol. i, of the Froccedings of the West London 

 Scientific Association has been published. It contains the inau- 

 gural address of the President, the Rev. G. Henslow, for 

 1875-6, and a report of the meetings to the end of last year. 



The system of forest conservancy which is proving so satis- 

 factory in India, is becoming imitated more or less in various . 

 parts of the world. In the Vilayet of Trebizond the virgin 

 forests cover an area of i, 00 d square miles, one half of which 

 belongs to the crown, and the other half, which consists mainly 

 of groves, situated in the vicinity of villages, is considered by the 

 inhabitants as belonging to the commons, and in a few cases to 

 private individuals. Most of the crown forests are in the districts 

 of Livanah, Adjarah, Batoom, Tsorook Soo, and Off on the 

 east ; of Trebizond, Ordoo, Guerela, and Aktshe Abad on the 

 west ; and Madjka, Kurtine, Kelkit, and Shagran on the south. 

 In these forests the pitch-pine, fir, ordinary pine, and beech 

 predominate. Chestnut, alder, elm, oak, ash, maple, and lime 

 are also everywhere and in great numbers. Boxwood grows 

 especially at Alina and Rijah, and the juniper at Kerasond, 

 Tinebali, and Livanah. The mean distatice of the forests from 

 the sea-shore is about fifteen miles. Although in general the 

 means of transport are wanting, there are many forests that can 

 be worked with comparatively small outlays for the construction 

 of short roads, in consequence of the proximity to the existing 

 high roads, such as the forests of Kerasond and Madjka, or 

 to rivers on which the timber can be floated, such as the forests 

 of Livanah and Sireboli. With the exception, however, of box- 

 wood, exported from Kiyeh and Atinah, and a little timber from 

 Batoom, no advantage is derived at present from the extensive 

 forests belonging to the crown. The timber and fire-wood used 

 -for local consumption is usually cut in the groves situated at no 

 great distance from the sea-shore, or near the villages, and which 

 are claimed by the inhabitants as belonging to them. In con- 

 sequence of these woods having been constantly and indiscrimi- 

 nately felled, and often burnt down for the purpose of obtaining 

 arable land, they are in a very poor condition. Of late, how- 

 ever, to prevent this destruction, forest guards have been 

 appointed under the orders of special officers. 



The Paris observatory has been opened again to public 

 inspection, on Thursday evenings. Applications must be made 

 by letter to the Secretary. 



Signor D'Alberiis left Somerset, in York Peninsula, on 

 May i8th last, on his exploring expedition to Ncav Guinea, 



