May io, 1903] 



NATURE 



2>7 



The current number of T/ie BniUer (May 5) contains repro- 

 ductions of Mr. Aston Webb's drawings of the proposed build- 

 ings to be erected in the Imperial Institute Road, South Ken- 

 sington, to accommodate the physics and chemistry departments 

 of the Royal College of Science. The original drawings are on 

 view at the Royal Academy. 



The " Statesman's Year-book," edited by Dr. J. Scott Keltie, 

 with the assistance of Mr. I. P. A. Renwick (Macmillan), has 

 been accepted as a trustworthy authority upon all matters of 

 political geography for so many years, that people familiar with 

 its pages, and therefore conscious of the extent and accuracy of 

 the information contained in them, regard it as one of the few 

 essential annuals. The volume for 1900, which has just been 

 published, is larger than any previous edition, and the numerous 

 rearrangements of territories which were made last year have 

 necessitated many changes in the text, several of the sections 

 having been almost rewritten. Four specially prepared coloured 

 maps are included, dealing with (l) the partition of North-east 

 Africa ; (2) the reorganisation of British Nigeria and the French 

 West African territories ; (3) the political partition of the Pacific ; 

 (4) the final arrangement of the boundary between British 

 Guiana and Venezula. The " Year-book " is thus an epitome 

 of recent geographical events as well as a manual of statistical 

 and historical information concerning the states of the world. 

 So long as the volume is kept so completely up to date as it is at 

 present, it is not likely to be superseded. 



In a short note in the current number of the Berichle, Dr. 

 Marckwald discusses some peculiarities shown by picric acid 

 and its solutions, in the light of the ionic hypothesis. Picric 

 acid, as usually obtained, has an intense yellow colour, but on 

 recrystallising from strong hydrochloric acid it becomes nearly 

 colourless. If this white crystalline mass is sucked nearly dry 

 at the filter pump and washed with a little water to remove the 

 adhering hydrochloric acid, the yellow colour at once returns. 

 The mother liquor, which at first has only a p.\le yellow colour, 

 also becomes more intensely coloured as water is added. Dr. 

 Marckwald shows that if it be assumed that picric acid is itself 

 colourless, but that the ions, C6H.2(N02)30, are coloured, all 

 these somewhat perplexing phenomena find an immediate ex- 

 planation in terms of the theory of electrolytic dissociation. 



The confirmation of the relations deducible by thermo- 

 dynamics as existing between the freezing-point and vapour 

 pressures of a very dilute solution, although of considerable 

 importance for the electrolytic theory of solution, presents great 

 experimental difficulties, especially as regards the vapour pres- 

 sure determinations. An ingenious method attacking this 

 problem is described in the current Zeitschrifl fiir physikalische 

 C/iemie, by Dr. R. Gahl. A measured volume of air is drawn 

 through the solution, such as hydrochloric acid, and this is 

 passed through pure water, the change of electrical conductivity 

 of which is measured. The number of cases in which such a 

 method can be applied is obviously restricted, but the accuracy 

 attainable appears to be of the order of 'ooi mm. of mercury. 



The additions to the Zoological Society's Gardens during the 

 past week include a Grys-bok {Raphiceros inelanotis) from South 

 Africa, a \ellow- whiskered Lemur {Levuir xanthotnystax) from 

 Madagascar, presented by Mr. J. E. Matcham ; a Violet- 

 necked Lory {^Eos riciniata) from Molluccas, presented by Mr. 

 H. R. Filliner; two Australian RAxh {Hallus pecloralis) from 

 New Holland, presented by Mr. C. J. Fox ; a Common Boa 

 (Boa constrictor) from South America, an Egyptian Eryx {Eryx 

 jaculus) from Egypt, presented by Mr. C. W. Lilley ; two Eyed 

 Lizards (Lacerta ocellata), European, presented respectively by 

 Miss Robinson and Miss Ash ; two Edible Frogs {Rana escti- 

 lento) from Biskra, presented by the Hon. Mrs. A. Cadogan ; a 

 NO. 1593. VOL. 62] 



Crowned Lemur (Lemur coronaliis'^, a Black Lemur (Lemur 

 ■niacaco), two Blackish Sternotheres (Slernolhoerus nigricans), a 

 Radiated Tortoise ( Testudo radiata) from Madagascar, a 

 Slender Loris (Loris gracilis) from Ceylon, two Amherst's 

 Pheasants ( Thaumalea picta, d ? ), ten Reeve's Terrapins 

 (Damonia reevesi), a Three-banded Terrapin (Cyclemmys tri- 

 fasciata) from China, a Grooved Tortoise (7<?.r/«rf(!> cakarala) 

 from Khartoum, too Roofed Terrapins (Kachuga tectum), a 

 Hamilton's Terrapin (Damonia hamiltoni) from India, a 

 Derbian Sternothere (Sternothoerns derbianiis), two Black 

 Sternotheres (Stertutfuerus niger) from West Africa, three 

 Chequered Elaps (Elaps leinniscatus) from South America, a 

 Glass Snake (Ophiosaurus apu^), European ; six Kentucky 

 Blind l<ish (Amblyopsis speloea) from Kentucky, deposited ; a 

 Brazilian Tapir (Tapirus americaiiu^, i ) from South America, 

 a Cape Hunting Dog {Lycaon pictus, 9 ) from South Africa, two 

 Siamese Pheasants (Euplocamus proela'us, £ 9 ) from Siam, two 

 Rufous-tailed Pheasants (Euplocavins erythropthalmus, & 9 ) 

 from Malacca, purcha.sed ; a Crowned Lemur (Lemur coro- 

 iiatus), an English Wild Cow (Bos taurus), born in the 

 Gardens. 



OUR ASTRONOMICAL COLUMN. 



Co.MKT GiACOBiNl (igoo a). — This comet has been in an un- 

 favourable position for observation during the past few weeks, 

 but is now rapidly leaving the sun, and may 'oe searched for 

 in the early morning. The following ephemeris is an abridg- 

 ment from one given by Herr A. Berberich, of Berlin, in the 

 Astronomische Nachrichlen (Qd. 152, No. 3636): — 

 Ephemeris for 12/1. Berlin Mean Time. 



1900. 



R.A. 



Decl. 



May 21 ... I 17 22 ... -i-24 218 



22 ... 16 27 ... 24 41-4 



23 ... 15 30 ... 25 1-2 



24 ... 14 31 ... 25 21-4 



25 ... 13 29 ... 25 41 -8 



26 ... 12 26 ... 26 2-6 



27 .. II 21 ... 26 23-6 



28 ... 10 13 ... 26 44-9 



29 .. 93 ... 27 6-5 



30 ... 7 50 ... 27 28-4 



31 ... I 6 34 ... 4-27 50-6 



At present the comet is moving slowly in a north-westerly 



direction through the constellation Pisces, almost in a line 



between j3 Arieles and a Andromedte. 



Coix)UR Screens for Refracting Telescopes. — The 

 Aitronoviische Nachrichten (Bd. 152, No. 3636) contains a 

 description of some experiments undertaken by Messrs. T. J. J. 

 See and G. H. Peters, at the United States Naval Observatory, 

 to determine the utility of viewing celestial objects through 

 variously coloured screens. It was thought that if a suitable 

 screen was chosen which would cut off the violet light of the 

 secondary spectrum shown by the lens, that a considerable im- 

 provement of the definition might be expected, and after trial of 

 several types of light filter, several were found which did 

 niaterially improve the seeing. The screen specially recom- 

 mended consists of a solution of picric acid and chloride of 

 copper in alcohol. This is applied in a small cell made to fit as 

 a cap outside the eyepiece of the telescope. It is thought that 

 the method may improve meridan work by furnishing better 

 defined star-discs, and also planetary micrometer measurements 

 on account of the diminution of irradiation. 



Photometric Revision of Harvard Photomktrv. — 

 The Harvard Photometry, showing the brightnesses of stars north 

 of declination —30", and of the sixth magnitude or brighter, was 

 compiled from observations made during the period 1879-82. 

 In 1 89 1, on the return of the photometer to Cambridge from 

 Peru, it was decided to redetermine the magnitudes of these 

 stars, and by the end of 1894 the work was almost completed. 

 Nearly all the observations were made by Prof. E. C. Pickering, 

 the Director of the Observatory of Harvard College, and the 

 results of the revision now form Part i. of the last issue of the 

 Annals of Harvard College Observatory, vol. xliv. 



