i86 



NA TURE 



[June 23, 1904 



Patent Office," which costs sixpence. The list consists of 

 two parts ; first, a general alphabet of subject headings, 

 with entries in chronological order of the works arranged 

 under these headings, and, secondly, a key, or a summary 

 of these headings shown in class order. The list comprises 

 2374 works, representing 3702 volumes. 



The series of eight lectures on " Physical Chemistry and 

 its .Applications," delivered some time ago by Prof. J. H. 

 van 't Hoff at the invitation of the University of Chicago, 

 has recently been translated into French by Prof. Corvisy 

 (.\. Hermann, Paris). No higher tribute to the intrinsic 

 merit of these most readable lectures could be desired, and 

 Ihey will no doubt be warmly received by a large circle of 

 l-'rench readers. 



SoMK noteworthy e.\perimental results communicated by 

 .Messrs. van Calcar and Lobry de Bruyn to the current 

 volume of the Reciteil des Travanx chimiqucs des Pays-Bas, 

 vol. .x.xiii. p. 218, show that considerable changes take 

 place in the concentration of solutions under the influence 

 of centrifugal forces. The concentration increases from the 

 axis of rotation towards the periphery, and the changes 

 have been accurately measured in the case of potassium 

 iodide and cane sugar. Portions of a solution of potassium 

 iodide of 02035 normal concentration, removed respectively 

 from points near the axis of rotation and some distance 

 away, were found to be 0-1065 normal and 0325 normal. 

 These portions of solution were removed after centrifuging 

 for three hours at the rate of 2400 revolutions per minute. 

 .■\ saturated solution of Glauber's salt, containing 8-8 per 

 cent. Na^SOj, deposited 57 grams of solid Naj.SO^.ioHjO 

 at the periphery after being rotated for five hours, and the 

 remaining solution was found to contain only 55 per cent, 

 of sodium sulphate. It is calculated that the applied force 

 acting on the molecules at the periphery (radius of rota- 

 tion =6 cm.) in these experiments was more than 400 times 

 greater than gravitational force. 



In the Revue de Metalhirgic for .April, M. H. Le Chatelier 

 re-states and explains his views on the constitution of the 

 carbon-iron alloys. He points out the importance of 

 classifying the constituents of heterogeneous bodies, and 

 again directs attention to the similarity between alloys and 

 igneous rocks. In chemical classification it is necessary 

 to give the chief place to the conception of phases, and to 

 regard chemical composition as of secondary importance. 

 If chemical composition alone were used for purposes of 

 classification, there would be no distinction, for example, 

 between crystallised granite and fused granite, although 

 the former contains three phases, quartz, felspar and mica, 

 and the latter contains only one phase. Moreover, it is 

 desirable to give names to the phases, even when they are 

 solid solutions of variable composition. One of the great 

 difliculties in determining the phases in the steels is that the 

 individual crystals are generally so minute that they cannot 

 be isolated, and their properties and chemical composition 

 cannot be exactly determined. Nevertheless, some progress 

 has been made in the recognition of the various phases 

 that may occur. M. Le Chatelier believes that these phases 

 include iron in its various allotropic forms ; carbon in the 

 form of graphite ; cementite, or Fe,C ; and many solid solu- 

 tions containing iron and either carbon, nickel, man- 

 gane.se, phosphorus, silicon, or other elements. Most of 

 these phases have not yet received names, but the highly 

 important carbon-iron solutions have been called troostite, 

 martensite, and austenite. The homogeneity of these 

 phases has been called in question, but the attempts to prove 

 ihai they are heterogeneous have not yet been successful. 

 NO. 1608, VOL. 70 1 



Difficulties are occasioned by the similarit\" of the proper- 

 ties of these three solutions, and the evidence that they are 

 distinct rests mainly on their appearance under the micro- 

 scrope after treatment by different reagents. It is scarcely 

 necessary to add that these views are not shared by some 

 students of metallography. 



OUR ASTRONOMICAL COLUMN. 



The Govekn.ment Ohserv.\tory, Bombay. — The report of 

 the Bombay Observatory for the year ending December 31, 

 1903, signed by the director, Mr. N. A. F. Moos, gives an 

 account of the many and varied observations carried out 

 there. The instrumental equipment is extensive and in 

 good order, the records of failure by the automatic register- 

 ing instruments being \erv few. 



The rainfall for the year was 8449 inches, a surplus of 

 9-33 inches above the .iverage of the twenty-four years 

 1873-1896. The daily wind pressures and temperatures 

 were recorded regularly, and many magnetic and seismo- 

 graphic observations were made daily. Routine observ- 

 ations with the transit instrument, to check the standard 

 clocks, were made at regular intervals, and a very good 

 time service was maintained at the docks and other public 

 places. The rating and adjustment of chronometers and 

 deck-watches for Government departments and ships, and 

 for private ship owners, formed an important part of the 

 year's work. 



Nebulous Are.is of the Sky. — In an article published in- 

 Popular Astronomy (No. 6, vol. xii.). Prof. H. C. Wilson, 

 of the Goodsell Observatory, discusses the subjective 

 existence of the large nebulous areas of the skv as described 

 by Sir William Herschel. He fully confirms Herschel's 

 observations, and considers that the negative results 

 obtained by Dr. Roberts last year must have been due to 

 unfavourable observing conditions. Further, he shows by 

 a reproduction of one of his own beautiful photographs- 

 of the Pleiades region, which was taken with a 6-inch 

 Brashear star-camera, that at least one of the regions de- 

 scribed by Dr. Roberts as containing no nebulosity is in 

 reality filled with nebulous matter, covering as many square 

 degrees as Herschel allotted to the whole of the nebulosities 

 in his fifty-two regions. 



Profs. Wilson and Payne intend transporting their photo- 

 graphic equipment to a station situated in the western 

 Montana mountains at an altitude of about one mile, so 

 that during July and .August they may test the suitability 

 of the atmosphere at that altitude for photographing the 

 nebulous patches of the .Milky Way, and, ff possible, obtain 

 further confirmatory photographs of Herschef's regions. 



Light Curve of 5 Cephei. — From an exhaustive dis- 

 cussion of the available data concerning the magnitude 

 variations of 5 Cephei. .M. Beliawsky, of St. Petersburg, 

 has derived the following elements : — 



Minimum 0=1840 .September 24-833d. M.T-. Bonn. 

 Period = 5-36642 days. 



The period between a maximum and the succeeding 

 minimum, according to the curve, is id- ii-i84h., and this; 

 value is very near the mean of the values obtained by five 

 previous workers. The light of the star varies between 

 magnitudes 437 and 3-57, and .M. Beliawsky gives the estim-- 

 ated magnitude for every o- r day between two succeeding 

 nvnima [Astronomiscl'c Si^tchrichten, No. 39-52)- 



PosiTiox OF THE .Axis OF RoT.^TiON OF M.\Rs. — Bulletin 

 No. 9 of the Lowell Observatory gives the results of a new- 

 determination of the position of the axis of rotation of 

 Mars, made bv Mr. Lowell. The direct method was em- 

 ployed, the position angle of the tangent to the limb at 

 the nearest point to the polar cap being measuied with a 

 micrometer. The varying inclination of this tangent to 

 the horizontal renders necessary the tilting of the observer's 

 eyes in some positions; presuming that this might affect 

 the resulting measures, iVIr. Lowell has differentiated the 

 results accordingly, calling them " e.xpurgated " or " un- 

 expurgated " as the time of observation was less or more- 

 than three hours after the horizontal position of the tangent.. 



