March 13, iSgoJj 



NATURE 



449 



Mr. John Murray has published the nineteenth edition of 

 " The Reign of Law," by the Duke of Argyll. 



The Amateur Photographer has issued its fourth "home 

 portraiture number." It reproduces one photograph each from 

 the work contributed by sixty competitors for prizes. 



In the Report of the U.S. Commissioner of Education for 

 the year 1887-88 it is stated that 48 educational institutions in 

 the United States receive the benefit of the national land grant 

 of 1862. Among these institutions are the Arkansas Industrial 

 University, the State Agricultural College at Colorado, the 

 Maine State College of Agriculture and the Mechanic Arts, the 

 Massachusetts Institute of Technology, the Missouri School of 

 Mines and Metallurgy, and the Scientific School of Rutgers 

 College. In 38 of the Colleges an oflScer of the Army or Navy 

 is detailed to act as professor of military science and tactics. 

 If a State has more than one school endowed by the national 

 land grant of 1862, the school which is reported by the 

 Governor of the State as most nearly meeting the requirements 

 of existing law is held to have the first claim to the officer 

 allotted to the State. 



M. A. Angot, of the French Meteorological Office, has 

 published in the Annates of that office a very careful discussion 

 of the diurnal range of the barometer, based upon the best 

 available data for all parts of the globe. After having given the 

 mean range for each month and for the year, he has calculated 

 the amplitudes and phases of the first four simple harmonic 

 oscillations into which the complex oscillation of the barometric 

 diurnal range may be resolved, and which may be considered as 

 the resultant of the superposition of two waves of different origin 

 and character. One of these, which the author terms the 

 thermic wave, is of a more or less complicated form in appear- 

 ance, and is easily explained as being produced by the diurnal 

 variation of temperature and by the differences that this variation 

 presents between neighbouring stations. The other, the principal 

 semi-diurnal wave, for which he has given the numerical law, 

 presents a much more simple form, and is not at all affected by 

 local conditions. It is possibly produced by the calorific action 

 of the sun upon the upper strata of the atmosphere ; but, as the 

 author states, this is still only an hypothesis, and the theory of 

 this part of the phenomenon remains to be established. His 

 conclusions upon the effect of the thermic wave are very interest- 

 ing, and the whole discussion will well repay a careful study. 



Mr, T. W. Baker writes to us that, in his note regarding 

 the meteor of March 3, he omitted to state the time of its 

 appearance, which was 7.28p.m. 



An important paper upon the crystalline allotropic forms of 

 sulphur and selenium is contributed by Dr. Muthmann, of 

 Munich, to the latest number of the Zeitschrift fiir Krystallogra- 

 phie. Besides the well-known rhombic pyramids and monoclinic 

 prisms, sulphur may, under certain conditions, be obtained in 

 a third crystalline modification, which has been termed by 

 Gernez " soiifre nacre." This third modification has been fully 

 investigated by Dr. Muthmann, and, in addition, a new fourth 

 totally distinct variety has been discovered. The third form is 

 best obtained by boiling about five grams of powdered sulphur 

 with 750 c.c. of absolute alcohol in a flask provided with an 

 inverted condenser for one hour, filtering through a warmed 

 funnel into a large flask heated to 70° C. in a water-bath, and 

 allowing the alcohol to slowly evaporate. After about twelve 

 hours a large deposit of brilliant tabular crystals is formed. 

 Similar crystals of the third variety may be obtained by agitating 

 a saturated alcoholic solution of ammonium sulphide with excess 

 of powdered sulphur, filtering, diluting with a little alcohol and 

 allowing to stand in a loosely covered cylinder. In a few hours 

 crystals are found deposited, often measuring a couple of centi- 



metres in length and 1-2 mm. thick. Another method which 

 yielded very beautiful crystals ofthis modification consisted in allow- 

 ing a solution of acid potassium sulphate to slowly diffuse into a 

 solution of sodium thiosulphate. In about four weeks' time, perfect 

 crystals, almost white in appearance, and exhibiting strongly the 

 mother-of-pearl lustre, were obtained. This third variety of 

 sulphur also crystallizes in the monoclinic system. The ratio of 

 its axes \% a:b -.c — i'o6o9 : i : 07094. The axial angle ^ = 

 88° 13'. The symmetry plane, b = (010)00^00, is so largely 

 developed as to give the crystals the appearance of plates. At 

 the edges of the plates the two primary pyramids (iii) - P and 

 (Iii) + P, a prism (210)00 ? 2, and a clinodome (oi2)i'l?oo are 

 well developed. These crystals are totally distinct from those 

 of the second modification ; the axial ratios of the latter are 

 a:b:c = 0*9957 : I : 0-9998 and fi = 84° 14'. Uyon the sides of 

 the vessel containing the alcoholic ammonium sulphide solution 

 prepared as above. Dr. Muthmann noticed curious tabular crys- 

 tals of hexagonal section, which immediately became altered 

 upon contact with a disturbingbody, such as a platinum wire or glass 

 rod. They were likewise found to consist of pure sulphur, and, 

 on optical and goniometrical examination, were found to consist 

 of a distinct fourth modification, also monoclinic. They greatly 

 resemble a rhombohedron with predominating basal plane. 

 They are best obtained by allowing to slowly evaporate in a tall 

 cylinder a saturated solution of sulphur in alcoholic ammonium 

 sulphide diluted with four times its volume of alcohol. The 

 temperature during this crystallization must not exceed 

 14° C. Occasionally in this experiment all four forms of sulphur 

 are obtained ; the surface is covered with crystals of the third 

 variety, tables of the fourth modification are deposited upon the 

 sides, and the base of the cylinder is spangled with rhombic 

 pyramids interspersed with monoclinic needles of the second 

 form. If crystals of the third variety are suspended in their 

 mother liquors and left for some days, they are converted into a 

 voluminous mass of minute rhombic pyramids. The conversion 

 into the more stable rhombic form is almost instantaneous if a 

 rhombic crystal be dropped into the liquid containing suspended 

 third variety crystals. The immediate alteration of crystals of 

 the fourth kind is even more remarkable, the mere movement of 

 the cover-glass, when examining them under the microscope, 

 being sufficient to instantly change the optical properties to 

 those of the rhombic form. It is interesting that this fourth 

 form of sulphur is isomorphous with the form of selenium 

 obtained by evaporation of a hot saturated solution in carbon 

 bisulphide. 



The additions to the Zoological Society's Gardens during the 

 past week include two Badgers {Metes iaxus) from Ireland, 

 presented by Mr. P. Bicknell ; a Grey Hypocolius {Hypocotius 

 ampetimis i ) from Scinde, presented by Mr. W. D. Cumming ; 

 a Rhesus Monkey {Macacus rhesus <? ) from India, a Spotted 

 Ichneumon {Herpestes nepatensis) from Nepal, deposited ; an 

 Axis Deer {Cervus axis), born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 

 Objects for the Spectroscope. 

 Sidereal Time at Greenwich at 10 p.m. on March 13 = 



9h. 25m. 5SS. 



