374 



NA TURE 



[February 20, 190? 



The question of the nature of red phosphorus is one that 

 has been frequently discussed, the general trend of the evidence 

 being to show that red phosphorus is a polymer of white phos- 

 phorus. Some new and interesting experiments on this subject 

 are contributed by Dr. R. Schenck to the current number of the 

 Berichle. Starting with the well-known equation of van 't Ho (T 

 -dCldt = l:C", in which C is the concentration, / the time, 

 and H the number of molecules taking part in a reaction, he 

 determines the velocity of transformation of white into red 

 phosphorus in solution in phosphorus tribromide at 172° C. and 

 184° C, and finds that K = 2is the only value of « which gives a 

 constant value for /■ in the velocity equation. From this the 

 conclusion is drawn that the equation (P4)o = Ps represents the 

 first stage of the conversion of white into red phosphorus. It 

 is, however, quite possible that this only represents the first 

 stage in the process, the differences in the properties of the two 

 varieties being so great that it is unlikely that they could be 

 caused by such a small change in molecular weight. 



An important discovery in medical science is announced by 

 M. Armand Gautier in the current number of the Comples 

 rendus. He has found that sodium methylarsenate, injected 

 into the blood in minute amounts, is an absolute cure for 

 malarial fever. Particulars are given of the treatment of nine 

 cases, all of which had been contracted in Africa, and which 

 were of such a severe type as to be refractory to large doses of 

 quinine. The nine cases were rapidly cured, two only showing 

 a slight relapse, and these yielded at once to a second injection. 

 The progress of the cure was followed in each case by the 

 examination of the blood, and the treatment was always fol- 

 lowed by the disappearance of the specific hematozoa. The salt 

 was also found to suppress entirely the anxmia associated with 

 malaria. M. Gautier regards the results as sufficiently definite 

 to authorise the substitution of this drug for quinine in pernicious 

 malaria, although it still remains for further researches to deter- 

 mine the best dose, and whether administration by the mouth or 

 hypodermically is to be preferred. 



A COMPLETE index of the first thirty volumes of the Journal 

 de Physique (1S72-1901), arranged both according to authors 

 and according to subject-matter of papers, has been announced. 



The behaviour of liquid sulphur dioxide as a solvent has been 

 very completely investigated by Messrs. Walden and Centners. 

 7,wer, an account of whose researches is contained in vol. xxxix. 

 of the Zeitsihrift fur physikalisehe Chemic (pp. 513-596). It 

 is found that liquid sulphur dioxide easily dissolves a large 

 number of (binary) inorganic salts and most salts of organic 

 bases. The solutions of these salts are good conductors of 

 electricity. The simple laws which regulate the conductivity 

 of aqueous solutions of salts are in general not valid for the 

 sulphur dioxide solutions. Amongst these may be mentioned 

 Kohlrausch's law of the independent wandering of the ions, 

 Ostwald's dilution law, the law according to which the molecular 

 conductivity approaches to a maximum with increasing dilution, 

 and the rule according to which the increase in the conductivity 

 with the dilution is the same for all binary salts. The con- 

 ductivity of solutions has been investigated at temperatures 

 ranging from the freezing point of liquid sulphur dioxide to its 

 critical point. The molecular conductivity increases at first 

 with the temperature, reaches a maximum at a temperature 

 dependent upon the nature of the dissolved salt, and then 

 decreases with a further rise of temperature, becoming finally 

 zero at the critical temperature, although the salts remain dis- 

 solved even at temperatures above the critical temperature. 

 The authors conclude from this observation that electrolytic 

 dissociation in solutions is an essential property of, or con- 

 ditioned by, the liquid state of aggregation. Determinations 

 NO. 1686, VOL. 65] 



of the molecular weight of dissolved salts by the boiling-point 

 method give values higher than the normal, from which it would 

 appear that the molecules of the dissolved salts are to a con- 

 siderable extent polymerised, or form complex associated 

 molecules containing molecules of the solvent. 



The additions to the Zoological Society's Gardens during the 

 past week include a Macaque Monkey (Macaciis cyiiomolgus) 

 from India, presented by Dr. Worley ; a Pochard (Fuligula 

 ferina), European, presented by Dr. H. S. Jameson ; a Smooth- 

 headed Capuchin {Cebits monachus) from South America, a 

 White-fronted Capuchin {Cebus albifrom), a Hoary Fox (Cants 

 vetiilus) from Brazil, a Blue-fronted Amazon (Chrysotis aesliva), 

 five Giant Toads [Bufo marittiis) from South America, an 

 American Green Frog (Rana halecina) from Central America, 

 two Gangetic Trionyx (Trionyx gangelictis) from India, 

 deposited. 



OUR ASTRONOMICAL COLUMN. 

 The New Bruce Spectrograph for the Yerkes- 

 Reiractor. — This instrument has been provided from funds 

 supplied in 1899 by Miss Catherine Bruce and the Rumford 

 fund of the American Academy of Arts and Sciences. The 

 arrangement o: the various parts has been designed in view of 

 obtaining the greatest possible rigidity and uniformity of 

 temperature, as the principal work for which it is to be em- 

 ployed is the determination of velocities in the line of sight. 

 To this end several departures have been made from ordinary 

 designs. The foundation consists of two castings rigidly con- 

 nected by a framework of steel tubes, one of these castings, 

 weighing about 200 pounds, being attached to the massive 

 terminal ring of the 4oinch refractor by eight bolts. The 

 collimator tube is firmly attached to this and the second casting, 

 which latter also holds the framework on which the prism train 

 is mounted. It was decided to use three pi isms of such angle 

 that the total deviation was 180°, thereby rendering the instru- 

 ment more compact and free from flexure. The optical train,^ 

 consisting of the correcting lens, coUimating lens, prisms and 

 camera lens, were made by Brashear from formul.v supplied by 

 Prof. Hastings. The correcting lens is 57 mm. aperture, and is 

 so designed that when placed 100 cm. in front of the focus of 

 the 40-inch for K 4500, the angular aperture of the large lens is- 

 not altered. The performance of this lens has been found to be 

 very satisfactory, rendering it possible to obtain a star spectrum 

 of uniform width from A 4300-A 4700. 



The collimator has a triple cemented lens of 51 mm. aperture 

 and 958 mm. focus. 



The first set of prisms, made from Mantois glass, was not 

 .satisfactory, and has been replaced by prisms made from glass 

 supplied by Messrs. Schott and Co., of Jena. These are not 

 perfect, but have given sufficiently good results to warrant theii 

 adoption. The refracting angles are about 634". 



Two camera lenses are proviiled, one being a Zeiss ana- 

 stigmat, aperture 71 mm., focal length 449 mm., the other a 

 triple cemented lens designed by Prof. Hastings, with aperture 

 of 76 mm. and focus 607 mm. 



For the region of H, the dispersion of this spectrograph is 

 almost identical with that given by the Mills and Potsdam III. 

 spectrographs. 



For temperature control the whole instrument is enclosed va 

 a double- walled case of aluminium ; thick felt is packed in the 

 space between the two metal sheets, and a helix of thin wire 

 distributed through this provides a convenient means of keeping 

 the temperature of the prism chamber almost constant for a 

 considerable time. For comp.arison spectra, electrodes of 

 titanium and iron are used, and also a vacuum tube of helium. 



In following, the method devised by Muggins of using the slit 

 plate as a reflector has been adopted, several variations being 

 made to avoid the inconvenience of having the two slit-jaws in 

 diflercnt planes with respect to the collimator axis. 



An extensive series of preliminary photographs has been 

 taken and reduced, and the instrument is now in use for 

 standard determinations of spectroscopic binaries, &c., which 

 can only be detected by the variable radial velocity deduced 

 from the displacement of spectrum lines {Aslropliysical journal, 

 vol. XV. pp. 1-27). 



