November i6, 1899] 



NATURE 



61 



among which are Mr. D. A. Rothrock's papers on point in- 

 variants for the Lie groups of the plane, and on differential 

 invariants derived from point invariants. To those interested 

 in the geometry of the triangle, Mr. Robert Judson Aley's list 

 of concurrent sets of three lines connected with the triangle will 

 prove a most useful synopsis for purposes of reference ; it 

 enumerates eighty-four different concurrences. The same writer 

 communicates a note on a new triangle and some of its properties ; 

 while Mr. C. E. Smith, of Indiana University, discusses the 

 geometry of Simson's line. A linear relation between certain 

 of Klein's X-functions and sigma functions of lower division 

 value is given in a note by Mr. John A. Miller. 



A FEW years ago Lussana discovered that the electric re- 

 sistance of aqueous solutions presented certain anomalies in the 

 neighbourhood of the temperature of maximum density, these 

 anomalies being represented by a point of inflection in the curve 

 expressing the relation between the resistance and the temper- 

 ature. In view of the objections raised against Lussana's work 

 and the intimate relation known to exist between the electric 

 resistance of a fluid and its viscosity, it occurred to Dr. G. 

 Pacher to examine whether any variations analogous to those 

 found by Lussana existed in the coefficient of viscosity of water 

 near the temperature of 4^ C. The results of Dr. Pacher's ex- 

 periments are described in a paper in the Atti del R. Istiluto 

 Veneto, Iviii. (2), pp. 785-814. The coefficient of viscosity was 

 found by observing the efflux of the liquid through a capillary 

 tiibe, Poiseuille's law being assumed, and the temperature was 

 maintained constant by immersing the tube in a water bath. 

 From the viscosity its temperature-coefficient was calculated and 

 represented graphically by a curve. The conclusions arrived at 

 are as follows : (i) In the neighbourhood of 4° the viscosity of 

 distilled water presents an anomaly indicated by a point of in- 

 flection in the curve connecting he viscosity with the temper- 

 ature ; (2) the temperature- coefficient of the viscosity presents a 

 maximum followed by a minimum between the temperatures of 

 3° and 6° ; (3) given the relation between the temperature- 

 coefficient of viscosity and that of electrical resistance, a similar 

 anomaly may be expected to exist in the electrical resistance of 

 distilled water ; (4) Lussana's results thus receive indirect con- 

 firmation from the present investigation. 



A POi'Ui.AR account of the possibilities and difficulties of 

 aerial navigation, based upon the scientific experiments made by 

 Langley, Lilienthal, Pilcher, Maxim and others, appears in the 

 current number of the Fortnightly Review. 



Sir John Evans's presidential address, on " The Antiquity 

 of Man, with especial reference to the Stone Age in Egypt," 

 delivered at the Birmingham and Midland Institute, has recently 

 been published. It is a brightly written sketch of a vast sub- 

 ject ; the more important approximate dates are given, which 

 is a useful feature. 



Those who are interested in Indian folk-lore must always 

 keep an eye upon X\\& Journal of the Asiatic Society of Bengal. 

 The first part of the new volume of the Anthropological Section 

 for this year contains a variety of interesting papers, amongst 

 which may be noted one, by Mr. C. C. Mitra, on folk-lore 

 about birds, and one, by Mr. C. A. Silberrad, on a rain- 

 compelling ceremony which is performed by women. 



A COPY of the Report and Transactions of the South-Eastern 

 Union of Scientific Societies, containing an account of the 

 proceedings at the fourth annual Congress held at Rochester in 

 May last, has been received. The Union systematises scientific 

 work among the different societies composing it, and in various 

 ways promotes the interests of science. Next year's Congress 

 will be held at Brighton early in June. 



From Messrs. Williams and Norgate's very useful " Book 

 Circular" (Scientific Series, No. 72), containing descriptive 

 NO. 1568, VOL. 61] 



notes on the contents of recent foreign publications, we ob- 

 tain the following announcements as to forthcoming scientific 

 works :— " Die Elemente der Entwicklungslehre des Menschen 

 und derWirbeltiere" is the^tle of a work by Prof, O. Hertwig, 

 of Berlin, which will shortly be published.— M. Le Dantec, 

 lecturer on embryology at the University of Paris, has written a 

 work entitled " Lamarckiens et Darwiniens," which will be 

 issued very shortly,—" Ueber Reduktionstheilung, Spindelbild- 

 ung Centrosomen und Cilienbildung im Pflanzenreiche " will be 

 the subject of the sixth part of Prof. E. Strasburger's " Mistolo- 

 gische Untersuchungen,"— The first part of " Nouveaux elements 

 de botanique," by Prof, Louis Crie, of Rennes, will soon appear, 

 and the second part will be published in the course of next year, 

 — The fourth edition of Prof. Lapparent's " Traite de Geologic " 

 will be issued in three parts. Of these, the first two will appear 

 almost immediately, and the third will appear in January. 



The difficulty of preparing metallic caesium is well known. 

 The metal has hitherto been obtained chiefly by the electrolysis 

 of the cyanide mixed with barium cyanide, but the unsatis- 

 factory character of this process is sufficiently shown by the 

 price of the product, which is about twenty-eight shillings a 

 gramme. It has been shown quite recently by Herren Graeffe 

 and Eckhardt that caesium can be prepared easily and with an 

 almost theoretical yield by the reduction of cjesium carbonate by 

 means of magnesium powder. The .mixture is heated in an 

 iron tube through which a slow current of hydrogen passes. 

 The metal distils over, and is collected under melted paraffin. 

 It has a silvery lustre with a slight yellow tint, and remains 

 bright under paraffin. On exposure to air it oxidises rapidly, 

 melts, and finally inflames. In its action on water it resembles 

 potassium, A previous attempt by Winkler to prepare caesium 

 by reducing the carbonate with magnesium failed, and led that 

 chemist to doubt the statement of Beketoff that the reducibility 

 of the alkaline carbonates increased with increasing atomic 

 weight of the metal. Herren Graeffe and Eckhardt, however,' 

 confirm Beketoff s conclusion, and show that caesium is more 

 easily reducible than rubidium, and rubidium than potassium. 



The additions to the Zoological Society's Gardens during the 

 past week include a Sykes's Monkey {Cercopithecus albigularis) 

 from East Africa, presented by Lord Alexander Thynne ; a 

 Macaque Monkey {Macacus cynomolgus) from India, presented 

 by Mr. W. J. Beard ; a Vervet Monkey {Cercopithecus lalandit) 

 from South Africa, a Viverrine Phalanger {Pseudochirus cooki) 

 from Tasmania, an Agile Wallaby [Mcuropus as^ilis) firom 

 Australia, a Brown Capuchin (Cebus fatuellus) from Guiana, 

 a Rufous-necked Wallaby {Macropus ruficollis) from New 

 South Wales, three Cardinal Eclectus {Eclectus cardinalis) from 

 Amboyna, four Serrated Terrapins (Chrysemys scripta), three 

 Prickly Trionyx {Trionyx spinifer), four Menobranchs (Nee- 

 turns maculatus), an Amphiuma (A/nphiuma means) from North 

 America, three Mute Swans [Cygnus olor), European, de- 

 posited ; a Black-backed Jackal (Canis mesomelas) from South 

 Africa, two Brazilian Caracaras {Polyborus brasiliensis), an 

 Anaconda (Eunectes murinus) from South America, purchased ; 

 a Spring- Bok {Gazella euchare) from South Africa, received in 

 exchange; a Hog Deer {Cervus porcinus), born in the 

 Gardens. 



OUR ASTRONOMICAL COLUMN. 



The Andromedes. — In respect to the reported observation 

 of Biela's comet, no confirmation of which, however, is yet to 

 hand, it will be well to keep careful watch on the character of 

 the second November display. The maximum is timed to occur 

 from the 23rd to the 27th, the approximate coordinates of the 

 radiant being 



R.A. = ih. 40m, 



Decl. = -f-44°; 



t 



^^mm 



