June 14, 1894] 



NA TURE 



157 



of sesquisulphide of phosphorus in carbon bisulphide and 

 evaporating. The second iodo-sulphide of phosphorus has the 

 composition PSl or P^SoTj, and was obtained by the action of 

 sulphuretted hydrogen upon the tri-iodide of phosphorus, PI3. 

 A lower temperature than tliat required for the formation of 

 the compound just described is advisable at first ; it should not 

 be much higher than 55', the melting point of the tri-iodide ; 

 before the conclusion of the reaction, however, it may safely be 

 raised to 120'. The solution of the product in carbon bisulphide 

 deposits red crystals of the new compound PSI. These crystals 

 are much more rapidly attacked by moist air than those of the 

 first iodo-sulphide, and the reaction is accompanied by the 

 liberation of fumes of hydriodic acid. They take fire upon 

 warming in the air, disseminating the odour of sulphur dioxide 

 and the violet vapour of iodine. Water dissolves them rapidly, 

 producing trisulphide of phosphorus and hyd riodic and phos- 

 phorous acids, and sulphuretted hydrogen is subsequently 

 evolved owing to the decomposition of the trisulsphide. The 

 third iodo-sulphide was obtained by reacting with excess of tri- 

 iodide of phosphorus upon the trisulphide. It is deposited 

 from carbon bisulphide in deep red crystals, very rapidly 

 decomposed by miist air, and its composition is P.jSr4. It thus 

 appears that iodine is capable of replacing more or less of the 

 sulphur contained in the sulphides of phosphorus, although it 

 does not succeed in totally eliminating sulphur (rom its com- 

 bination with phosphorus. M. Ouvrard has also obtained 

 several new halogen derivatives of the sulphides of arsenic and 

 antimony. Eugli-h readers of the original paper cannot but be 

 sorry, however, that M. Ouvrard employs the old notation, 

 which renders it difficult at first sight to follow the equations 

 representing the reactions. The formulae above given are 

 translated into the modern notation now universally employed 

 in this country and Germany. 



The additions to the Zoological Society's Gardens during the 

 past week include a Macaque Monkey (Macacus cynomolgus, 



9 ) from India, a White-throated Capuchin [Cebus hypolcttcus) 

 from Central America, presented by Mr. F. Erskine Paton ; a 

 < irey Ichneumon {Hii-peites gristles) from India, presented by 

 Miss Florence Marryat ; two Common Peafowl {Pavo crisiatiis, 



' 9 ) from India, presented by Mr. A. Tannenbaum ; a Putlf 

 -Adder ( Vipera arietans) from South Africa, presented by Mr. 

 I. E. Matcham ; four Common Snakes {7 ropidonotits ttatrix), 

 a Common Viper (Vipera, btrus), British, presented by Mr. 

 Harold Attewell ; a Smooth Snake {Coroiiella la-vis) British, 

 presented by Mr. Harry Furniss ; a Natterjack Toad {Biifo 

 calamita), British, presented by Mr. F. Wallace ; a Raven 

 {Con-US corax), British, presented by Mr. Robert O. Callaghan ; 

 two Cape Crowned Cranes (Biilt-arica chrysopclargtis) from 

 South Africa, four Yellow-bellied Xiothrix {Liotlirix /ulcus), 

 two Hamadryads {Ophiopkagus elaps) from India, deposited; 

 an Ashy-black Macacjue (Macacus ocreatus, i ) from the East 

 Indies, a Beech Marten (Muslela foina) from Russia, a Red 

 and Yellow Macaw (Ara chloroptera) from South America, a 

 Yellow-headed Vulture (CalharUs urubilinga) from Brazil, a 

 Turkey Vulture (Calhartcs aura) from America, a Guianan 

 Crested Eagle (Morphnus i^uianensis) from the Amazons, pur- 

 chased ; an English Wild Cow (lios taurtis, var.), three Varied 

 Rats (Tsomys varicgalns), a Bennetts Wallaby (Halmalttrus 

 iennetii), born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



Report of tkk Astronomer-Roval for Scotland.— 

 The fourth annual report of Prof. Copeland on the Royal 

 Observatory, Edinlnirgh, informs us that greit progress has 

 been mule in the construction of the new Observatory. The 



N O. 1285, VOL. 50] 



masonry of all the buildings is complete, and some parts are 

 ready for the internal fittings. 



A comparison of the earlier Edinburgh star places with the 

 catalogue of the Astronomischf Geselhchaft has shown the 

 necessity of a complete new reduction of the observations, in 

 order to bring them into line with modern practice in this kind 

 of work. For this purpose considerable progress has been 

 made in an investigation of the errors of the transit instrument. 



.\t the request of M. d'Abbadie, of the Paris Academy of 

 .Sciences, a bifilar pendulum was temporarily erected on the 

 rock at Calton Hill on March 24. This extremely sensitive 

 instrument, constructed by Mr. Hoiace Darwin on a principle 

 suggested by Lord Kelvin, indicates the minutest change of level 

 in the foundation to which it is attached. Prof. Copeland hopes 

 shortly to commence a series of systematic observations in con- 

 junction with allied observations made by M. d'Abbadie nearly 

 on the same meridian in the south of France. These investi- 

 gations will probably show if any considerable tilt takes place 

 at the same time at both stations. It is thought that the bi- 

 filar pendulum may serve to detect the occurrence of sudden 

 displacements in the foundations of observatories. 



Award of the Watson Medal. — At Washington a few 

 weeks ago Mr. .S. C. Chandler was awarded the Watson medal 

 by the National Academy of Sciences. A description of the 

 founding of the award and the work of previous recipients, 

 given by Mr. John Ritchie, jun., in the Boslini Commotiwealtk, 

 recalls a few facts of interest. Prof. J. C. Watson, the founder 

 of the award, was for many years professor of astronomy and 

 physics in the Universities of Michigan and Wisconsin, and for 

 some time previous to his decease was director of the Washburn 

 Observatory at Madison. His treatise on theoretical astronomy 

 is known to every computing astronomer. During the later 

 years of his life he devoted his attention to the minor planets, 

 of which he discovered twelve. It is common knowledge that, 

 at the eclipse of July 29, 1878, he and Dr. S*ift reported 

 observations of an intra-mercurial planet, and he believed in the 

 existence of such a body up to his death in 1S80. .\t his death 

 he left his estate, some family legacies excepted, in trust to 

 the National Academy of Sciences, the fund having since been 

 designated the Watson Fund. The amount of money realised 

 was in all some twenty or thirty thousand dollars. The income 

 of this is to be expended for the promotion of astronomical 

 science, specific provision being made for the presentation of a 

 gold medal and a gratuity of one hundred dollars in gold coin, 

 from time to time, to an astronomer who shall have accom- 

 plished work of high merit. He nominated as trustees of his 

 fund his friends Hilgard, Coffm and Newcomb, with provision 

 for the appointment of their successors. The high quality of 

 the tiust has been continued by the selection of Dr. B. A. Gould 

 and Prof. Asaph Hall as successors to Hilgard and Coffin, who 

 passed away some three years ago. Four medals only have 

 been given : the first to Dr. B. A. Gould in 1S87 ; the second 

 to Prof. Edward .Schnnfeld, Director of the University of Bonn, 

 in 1S88; the third to Dr. Arthur Auwers, of Berlin, in 1S91 ; 

 and the fourth to Mr. Chandler. It need hardly be said that 

 the award was chiefly given to Mr. Chandler for his brilliant 

 investigations on the variations of latitude. 



Two New Catalogues. — Astronomisdu Nachrickttn No. 

 3232 contains a long list of stars with remarkable spectra, 

 observed by the Rev. T. E. Espin. The catalogue comprises 

 167 stars, most of which have not had their spectra previously 

 recorded, 206 stars found to have spectra belonging to Type 

 III., and a list of 136 stars, of which it is doubtful whether they 

 belong to Type II. or HI. Nos. 3233 -34 of the same publi- 

 cation contain a catalogue of 187 new double stars discovered 

 with the iS[. inch refiactor of the Deerhorn Observatory, 

 U.S.A., and measures of 152 double stars, by Prof. G. W. 

 Hough. 



THE DENSITY OF NITROGEN GAS.^ 



TN a former communication- I have described how nitrogen, 



prepared by Lupton's method, proved to be lighter by 



about i/iooo pan than that derived from air in the usual manner. 



_' "On an Anomaly encountered in Determinations of the Density ot 

 NilroRen Gas." A paper read before the Koval Society on April lo, by Lord 

 Raylelgli, Sec. R.S. 



3 "tjn the Densities of the Principal Gases," Roy. Soc. Proc. vol. liii. 

 p. 146, 1893. 



