February i, 1894] 



NA TURE 



123 



We have received the Agricultural Gazette of New South 

 Wales for October, 1893, containing, among other papers, an 

 elaborate one by Mr. N. A. Cobb, on "Plant Diseases and 

 their Remedies." The present instalment is entirely devoted 

 to the very numerous diseases which attack the sugar-cane ; 

 copious illustrations are given of its animal and vegetable 

 parasites. 



Mr. W. Trelease reprints, from the fifth annual Report of 

 the Missouri Botanical Garden, an elaborate illustrated paper on 

 sugar maples. He recognises ten species of Acer natives of the 

 United States, and classifies them under five groups — the bush 

 maples, vine maples, sycamore maples, soft maples, and hard 

 or sugar maples. The sugar maples are Acer grandiJentatum, 

 sacchariim, and Floridanutn. Linnaeus's Acer saccharinum is 

 not a sugar maple at all, but is the silver maple belonging to the 

 group of soft maples. 



A NEW method of preparing phosphorus is described by 

 Messrs. Rossel and Frank in the current issue of the Berichte. 

 By the use of aluminium as reducing agent it is shown that 

 phosphorus may be directly obtained from any mineral phos- 

 phate, and the method lends itself admirably to lecture-table 

 demonstration. When ordinary microcosmic salt, hydrogen 

 ammonium sodium phosphate, is fused in a porcelain crucible 

 until it is converted into sodium metaphosphate, and aluminium 

 turnings are dropped into the liquid, the flame of burning 

 phosphorus at once appears. If the experiment is conducted 

 in a glass tube in a slow current of dry hydrogen the phos- 

 phorus distils into the cooler part and without the formation of 

 any phosphoretted hydrogen. The residue consists of alumina, 

 sodium aluminate, and a phosphide of aluminium of the com- 

 position AI3PJ. This latter substance may be isolated as a 

 grey crystalline powder by leading phosphorus vapour over 

 aluminium heated in a combustion tube ; it is unchanged by 

 further heating, but is decomposed by water with formation of 

 aluminium hydrate, phosphoric acid, and phosphoretted 

 hydrogen. In the preparation of phosphorus by the method 

 above described it is consequently impossible to obtain more 

 than thirty per cent, of the phosphorus contained in the 

 mineral phosphate employed. But it is found that the 

 phosphide is totally decomposed by heating with silica, 

 and hence if the mineral phosphate is previously mixed with 

 some form of silica the whole of the -phosphorus is liberated, 

 and the reaction proceeds in a regular and readily controllable 

 manner. Bone meal, powdered phosphorite or fossil phos- 

 phate, magnesium pyrophosphate, calcium metaphosphate, or 

 any ordinary available phosphate, may be employed. Care 

 must be taken, however, not to employ superphosphates con- 

 taining admixed calcium sulphate, such as are commonly ob- 

 tained for agricultural purposes by treatment with sulphuric 

 acid without separation of the sulphate, for the sulphate is sud- 

 denly decomposed by the aluminium when a certain temperature 

 is attained, with explosive force. Superphosphates obtained by 

 treatment with hydrochloric instead of sulphuric acid may be em- 

 ployed with perfect safety, as chlorides are not explosively 

 decomposed by aluminium. The new mode of preparing phos- 

 phorus may be conveniently illustrated upon the lecture-table 

 by placing in a combustion tube a yard long, traversed by a 

 slow current of hydrogen, a mixture of two and a half parts of 

 aluminium, six parts of sodium metaphosphate, obtained by 

 heating microcosmic salt, and two parts of finely divided pre- 

 pared silica, and heating until the reaction commences. This 

 is notified by a sudden brilliant incandescence, and phosphorus 

 is observed to rapidly condense in globules in the cooler portion 

 of the tube, at the end nearest the draught-hole into which the 

 escaping hydrogen is led. 



NO. 12 56, VOL. 49] 



An interesting paper upon the interaction between oxygen 

 and phosphoretted hydrogen is contributed to the Zeitschrijtjiir 

 Physikalische Chemie by Dr. Van de Stadt. It is shown that 

 the two gases instantly combine, with the appearance of flame, 

 when they are allowed to mix under diminished pressure. The 

 combination occurs under these circumstances in the proportions 

 of two volumes of hydrogen phosphide to three volumes of 

 oxygen, the product being phosphorous acid. When, however, 

 the oxygen is admitted very slowly, or the two gases are allowed 

 to mix by diffusion under a pressure not exceeding 50 mm. 

 equal volumes appear to react with production of a greenish 

 flame, liberation of hydrogen, and formation of a crystalline 

 deposit on the walls of the vessel. The crystals melt at about 

 80°, and appear to consist of the little-known metaphosphorous 

 acid HPO2 ; they are deliquescent, but after combination with 

 sufficient water vapour to produce ordinary orthophosphorous 

 acid the substance solidifies again. If the pressure is greater 

 than 50 mm. both the meta and ortho acid are produced together 

 with more or less free hydrogen. When the pressure is 

 gradually reduced the gases combine at a certain low pressure 

 with explosion. It is somewhat remarkable that the influence 

 of moisture is directly opposite to that usually observed, for 

 instead of facilitating the combination it greatly retards it. 



Notes from the Marine Biological Station, Plymouth. — 

 Recent captures include two specimens of a small well-marked 

 species of Doris, new to Britain, and probably to science. The 

 tow-nets, on the other hand, have not yielded much of unusual 

 interest lately, the chief contents being Copepods, Sagitta, 

 Cirrhipede Naiiplii, Polychsete larvae, and Teleostean ova. 

 The breeding season of a large number of both Fishes and 

 Invertebrates has, however, recently commenced, including 

 the Nemertine Lineus obscurus, the Polychaste Phyllodoce, the 

 MoUusca Purpura laplllus and Acanthodoris pilosa, the Crus- 

 tacea Cravgon vulgaris zx^A Eurynome aspera, and the Ascidian 

 Botryllus violaceus. The Anthozoa Alcyonium digitatum and 

 Cereus pedunculatus are still breeding. 



The additions to the Zoological Society's Gardens during 

 the past week include two Black-eared Marmosets {Hapale 

 penicillata) from South-east Brazil, presented by Mrs. G. E. 

 Russell ; two Weka Rails (Ocydromus anst rails) from New 

 Zealand, presented by the Hon. Lancelot Lowther ; a Cross- 

 bill Loxia curvirostra) British, presented by Mr. W. S. 

 Berridge ; a King Snake {Coluber geiulus) from Florida, pre- 

 sented by Mr. Lawson Reuss ; a Rose-ringed Parrakeet 

 {Paler ornis docilis) from West Africa, presented by Mr. J. 

 Hickman ; a Ring-tailed Coati {Nasua rufa) from South 

 America, deposited ; two Abyssinian Guinea Fowls {Nutnida 

 ptilorhyncha) from Somaliland, two Burrowing Owls {Speotyto 

 cunicularia) from America, eight Undulated Grass Parrakeets 

 {Melopsittacus undnlatus) from Australia, purchased. 



OUR ASTRONOMICAL COLUMN. 



Jupiter's Satellites in 1664. — In the New York Nation, 

 Mr. D. C. Oilman calls attention to an interesting letter of 

 John Winthrop, written in 1664 to Sir Robert Moray. The 

 letter is printed in the Proceedings of the Massachusetts 

 Historical Society, June, 1878, and the following is an extract 

 from it : — 



' ' Havinge looked upon Jupiter with a Telescope, upon the 6th 

 of August last, I saw 5 (?) Satellytes very distinctly about that 

 Planet : I observed it with the best curiosity I could, taking 

 very distinct notice of the number of them, by several! aspects 

 with some convenient tyme of intermission ; & though I 

 was not without some consideration whether that fifth might not 

 be some fixt star with which Jupiter might at that tyme be in 

 neare conjunction, yet that consideration made me the more 



