January 25, 1900] 



NA TURE 



305 



Ualfour, F.R.S. ; and 

 Richard Hargreaves. 



A Textbook of Arithmetic," by Mr. 



A NEW monthly magazine — The International Monthly — 

 made its appearance at the beginning of this year, the pub- 

 lishers being the Macmillan Company. The periodical is a 

 serious addition to contemporary literature, and contains in- 

 structive essays on progress in several departments of knowledge. 

 Science is represented by an article, by Prof. N. S. Shaler, on 

 the connection between solar energy and terrestrial formations 

 and phenomena ; and Prof. John Trowbridge gives an outline 

 of recent advances in physical science. For each department of 

 the magazine, there is an editor in F" ranee, another in Germany, 

 and a third in England, as well as one in the United States. 



A SERIES of monthly star maps, prepared by Mr. Walter B. 

 Blaikie for the Scottish Provident Association, provides a concise 

 source of reference to the ordinary observer not possessing any 

 special astronomical knowledge. The maps give a planispheric 

 projection of the heavens, as seen from London, for the first 

 day of each month at lo p.m., each map being divided into tvvo 

 portions, showing the northern and southern aspects respec- 

 tively. A considerable amount of useful information is given 

 in the letterpress accompanying the maps, including short de- 

 scriptions of the more interesting celestial objects, and par- 

 ticulars respecting the planets visible during each month. 



Thk sixth volume in the biological collection of the 

 "Scientia" series of scientific treatises, published by Messrs. 

 G. Carre and C. Naud, Paris, is concerned with the " Evolu- 

 tion du Carbone et de 1' Azote," by Dr. P. Maze. The three 

 chapters which make up the volume deal respectively with the 

 origin of carbon in the organic world, the origin of organic 

 nitrates, and the decomposition of organic compounds. Many 

 subjects of interest to chemists and plant physiologists are 

 passed in review: for instance, the mjchanism of carbo- 

 hydrates in leaves by means of diastasis, the assimilation of the 

 organic carbon from the soil, and formation of fatty substances, 

 the formation of the quaternary compounds in the higher 

 plants, and the relation of various forms of life to the proportion 

 of carbon dioxide in the atmosphere. 



Messrs. Williams and Norgate's current " Book Cir- 

 cular " contains the following announcements : — Dr. R. Hartig 

 has thoroughly revised his " Lehrbuch der Baumkrankheiten," 

 and will shortly issue the third edition under the title " Lehr- 

 buch der Pflanzenkrankheiten." — A second revised and enlarged 

 edition of Dr. Julius Wiesner's "Die Rohstoffe des Pflanzen- 

 reichs " is in preparation. The first part will be issued 

 shortly. — Dr. Eugen von Halacsy will publish very shortly 

 the first part of a flora of Greece, Epirus, and the Ionian 

 Islands, under the title of "Conspectus Florae Graecae." The 

 first instalment will consist of some i6o pages, and it is 

 expected that the work will be complete in about eight parts. 

 — The first part of the handbook of the Siphonogamae, by 

 Drs. D.illa Torre and Harm.s, will very shortly be published 

 under the title "Genera Siphonogamarum." — A .supplementary 

 volume to Beilstein's " Handbuch " is being prepared by the 

 German Chemical Society under the editorship of Prof. Paul 

 Jacobson, and will be issued in parts during this year. 



The system of determining latitudes by observing at groups 

 of stations close together instead of at a single station, was again 

 given a trial by officers of the Survey of India department in 

 1898, and is referred to in the report which has recently been 

 published. The system originated with Lieut. J. Herschel, 

 several years ago, but was allowed to drop, because that oflScer 

 was removed from the work before he had fully elaborated it. 

 For the new experiments the longitudinal station at Agra was 

 NO. 1578, VOL. 61] 



selected as the central point, but for reasons which had not 

 been foreseen it was found impossible to connect the outlying 

 stations by a sufficiently rigorous triangulation for a proper com- 

 parison of the observed and computed azimuths. The latitude 

 observations led to intere.sting results, and opinion is express^ d 

 that in more favourable country the system will prove highly 

 valuable. 



The dilution law given by Ostwald in 1888, K= 7-3 rp 



(where a is the percentage dissociation and V the volume of 

 liquid containing one molecular weight of the binary electrolyte), 

 was a most important step forward in the study of solutions. 

 But as further investigations were made on this subject, it was 

 found that this dilution law holds only for weak acids and bases, 

 and not for salts, strong acids and strong bases. The Ostwald 

 expression was derived directly from the law of mass action, 

 but subsequent attempts to modify it in the direction of in- 

 cluding strong electrolytes were empirical. Thus Rudolphi's 



and van 't Hofif's K ■ 



were ad- 



" -(I - a)^y' """ '"^" ^ """ " " - (I - apr 

 vanced in 1895, ^^'^ ^^^ latter, which can be more compactly 

 written A'= CiVC,"^ (where C,- denotes the volume concen- 

 tration of the dissociated portion and C, that of the un- 

 dissociated salt), represents the facts fairly well for 

 " strong " electrolytes. Since there is no sharp line 

 of demarcation between strong and weak electrolytes, 

 it follows that there must be electrolytes which are on the 

 border line between these two classes, and for which neither 

 formula holds with accuracy. In the current volume of the 

 Zeitschrtft fiir physikalische Chemie, Dr. W. D. Bancroft seeks 

 to replace these by a third formula, which, though empirical 

 and indeterminate, may describe all binary electrolytes. This 

 formula is A' = Ci"/Cs, including both the Ostwald and van 't 

 Hoff expressions as special cases. Dr. Bancroft points out that 

 the simplest way of determining whether the general formula 

 A' = C;"/C, does or does not apply is to plot the value of log Ci 

 against log C, as ordinates. If the formula applies, the result- 

 ing curve will be a straight line, and the slope of the line gives 

 the value of n. Values are given in the paper for solutions of 

 potassium, sodium, lithium, ammonium and hydrogen chlorides, 

 sodium potassium and silver nitrates, potassium iodide and 

 caustic potash, and with the exception of the most concentrated 

 solutions, the data lie absolutely on straight lines ; the values 

 of n found varying from 1*36 to I 55. A theoretical explanation 

 of these facts would be of the greatest interest. 



The additions to the Zoological Society's Gardens during the 

 past week include a Vervet Monkey (Cercofitkecus lalandii) 

 from South Africa, presented by Mr. A. Althorp ; a Woodcock 

 {Scolopax rusticula), British, presented by Mr. W^ A. Beau- 

 clerk ; a Short-eared Owl (Asia brachyotus) captured in the 

 Indian Ocean, presented by Dr. A. E. Prest Hughes ; two 

 White-headed Sea Eagles {Haliaelus leucocephalus) from North 

 America, presented by Mr. Henry Anger ; a Laughing King- 

 fisher (Dacelo gigatttea) from Australia, presented by Mr. J. 

 Kirkland ; two Triangular-spotted Pigeons (Columba guinea) 

 from South-West Africa, presented by Mr. J. Parminter ; two 

 Wagler's Terrapins (Hydraspis wagleri) from Brazil, six 

 Blanding's Terrapins [Emys dlandingi), a Grass Snake (Contia 

 venialis), a Mocassin Snake (Tropidonotus fasciatus) from 

 North America, a Flat-backed Tortoise {Testudo platynota) 

 from Burmah, an Indian River Snake {Tropidonotus piscator), 

 an Indian Eryx {Eryx johni) from India, ten Reeve's Terrapins 



{Datiionia reevesi) from China, two Chelodines {Ckelodina, 



sp. inc.) from Australia, a Royal ^yihon {Python regius) horn 

 South- West Africa, deposited ; eight Burrowing Owls (Speotyto 

 cunicularia) from South America, purchased. 



