8o 



NA TURE 



[May 25, 1893 



A SECOND edition of Mr. W. \V. Rouse Ball's "Short 

 Account of the History of Mathematics" (reviewed in Nature, 

 vol. xxxix. p. 265) has been issued by Messrs. Macmillan and 

 Co. The author lias revised the book and made some changes 

 in detail, but he explains in the preface that the general 

 character of the work — as a popular account of the leading 

 facts in the history of mathematics — remains unaltered. 



Messrs. Cassell and Co. have published a fifth edition of 

 "The Field Naturalist's Handbook," by the late Rev. J. G. 

 Wood and the Rev. Theodore Wood. 



Messrs. Asher and Co., Berlin, have begun the publication 

 of a series of reprints of remarkable writings and maps relating 

 to meteorology and earth-magnetism. The series is handsomely 

 printed, and edited by Prof. G. Hellmann. The first two num- 

 bers are L. Reynmann's " Wetterbiichlein von wahrer 

 Erkenntniss desWetters" (1510), and Pascal's " Recit de la 

 Grande Experience de I'liquilibre des Liqueurs " (1648). 



'Messrs. C. Griffin and Co. have published the tenth 

 annual issue of the "Year- Book of the Scientific and Learned 

 Societies of Great Britain and Ireland." The work comprises 

 lists of the papers read during 1892 before societies engaged in 

 fourteen departments of research, with the names of the 

 authors. 



Messrs. Friedlander & Son, Berlin, have published an in- 

 augural dissertation, prepared with a view to the attainment of 

 adoctor s degree at Gcittingen, by Johannes MUller, embodying 

 the results of researches on the anatomy of Composilce. The 

 essay is illustrated with four plates. 



A CATALOGUE of the types and figured specimens in the 

 geological department of the Manchester Museum, Owens 

 College, by Herbert Bolton, has been issued as one of the 

 " Museum Handbooks." In the same series appear an " Out- 

 line Classification of the Vegetable Kingdom," by F. E. Weiss, 

 and a second edition of Prof. Milnes Marshall's " Outline Classifi- 

 cation of the Animal Kingdom." 



The Geological and Natural History Survey of Minnesota has 

 published as one of its Bulletins (No. 7) a volume on "The 

 Mammals of Minnesota." It is described on the title-page as 

 "a scientific and popular account of their features and habits." 

 The work is illustrated with twenty-three figures and eight 

 plates. 



A WORK on the "Geology of the Eureka District, Nevada," 

 with an atlas, by Arnold Hague, has been published by the 

 United States Geological Survey. It forms the twentieth 

 volume of the Survey's "monographs." The author explains 

 in the preface that the work is purely geological in its scope and 

 is mainly a careful study and survey of a comparatively small 

 block of mountains, which may be designated the Eureka 

 Mountains, but which should not be confounded with the 

 Eureka mining district, as several other well-known but less 

 important mining districts lie wholly within the same mountain 

 area. 



The first part ot M. E. Burnat's important Flore des Alpes 

 Maritimes has just been published. 



A REPORT of the results so far obtained from Bornmiiller's 

 botanical travels in southern Persia is published in the MUthcil- 

 uitgen of the Thuringian Botanical Association. 



Dr. p. H. Mell has prepared for the U.S. Department of 

 Agriculture a valuable report on the climatology of the cotton 

 plant. 



An important series of well-crystallising double halogen salts 

 of tellurium with potassium, rubidium, and cssium, have been 



NO. 1230, VOL. 48] 



prepared by Mr. H. L. Wheeler, and are described in the 

 current number of the "Zeitschrift (tir Anorganische Chemie." 

 They correspond to the general formula MjTeRj, where M 

 represents potassium, rubidium, or caesium and R chlorine, 

 bromine, or iodine. They all crystallise in octahedrons belong- 

 ing to the cubic system, in this respect resembling the platino- 

 clilorides and other kindred double halogen salts of that type. 

 The crystals of the chlorides possess a bright-yellow colour, 

 those of the bromides various shades of deep red, while those 

 of the iodides are quite black and opaque. In order to prepare 

 the chlorides, tellurium is converted into tellurious acid by means 

 of nitro-hydrochloric acid ; the solution is evaporated to dryness, 

 and the residue dissolved in hot hydrochloric acid. Upon 

 adding to the solution of tellurium tetrachloride so obtained an 

 aqueous solution of the chloride of the alkali metal, a crystalline 

 precipitate of the double chloride is obtained. In the case of 

 the ca;sium salt, CSoTeClu, a precipitate is obtained even in 

 very dilute solutions, owing to the difficult solubility of the salt. 

 Upon 'ooiiing the precipitate dissolves, and on cooling brilliant 

 little yellow octahedrons are deposited. The presence of excess 

 of either cassium chloride or tellurium tetrachloride is quite 

 immaterial ; indeed, the salt may be recrystallised from a solu- 

 tion of either. Water at once decomposes it, with producion 

 of a voluminous white precipitate of tellurious acid IIoTtOj. 

 It is only stable in solution in presence of a little free hydro- 

 chloric acid. Concentrated hydrochloric acid precipitates it 

 from solution in the form of microscopic oclahedra. The 

 rubidium salt, RbjTeClo, is more soluble so that precipita- 

 tion only occurs in concentrated solutions. The crystals, more- 

 over, are usually much larger than those of the cxsium salt. 

 The potassium salt, KoTeClg, is much more soluble, and is 

 even deliquescent. An excess of tellurium tetrachloride is 

 necessary in its preparation, and it is best obtained in good 

 crystals by spontaneous evaporation of a dilute hydrochloric 

 acid solution. 



The bromides are obtained by dissolving finely divided 

 elementary tellurium and caesium bromide in dilute hydrobronic 

 acid containing excess of bromine. In the preparation of the 

 cresium salt, CsuTeBr,,, the solution is effected at a moderaiely 

 elevated temperature, and the concentrated solution deposits 

 large brilliant red octahedrons of the salt upon cooling. The 

 rubidium salt, Rh^TeBr,,, is readily obtained in magnificent 

 deep red octahedrons by spontaneous evaporation of the solu- 

 tion prepared at the ordinary temperature. In preparing the 

 potassium salt, if a hot solution is made, octahedral crystals of 

 the anhydrous salt, K^TeBrg are obtained, but if the con- 

 centration is effected by spontaneous evaporation light red 

 coloured rhombic crystals of a hydrated salt, K2TeBrg"2H^,0, 

 are deposited. The iodides are prepared by addition of the 

 alkaline iodide to a solution of tellurious acid in hydriodic 

 acid. The cresium salt, Cs.jTeIg, is so difficultly soluble that 

 it was only obtained as a finely divided black powder. The 

 rubidium salt, however, RboTelg, is more soluble and is 

 precipitated in microscopic black octahedrons. The potassium 

 salt is deposited in the hydrated form, K.jTeI|j'2H.,0, in 

 long monoclinic prisms which lose their water of crystallisation 

 at 100- 115° and become converted into a dull black powder 

 consisting of the anhydrous salt. 



Simultaneously with the above work of Mr. Wheeler, Drs. 

 Muthmann and Schiifer, of Miinich, have been engaged in 

 investigating the formation of double halogen salts of 

 the alkali melals with tellurium and selenium, and in 

 the current number of the "Berichte," an account of some 

 corresponding selenium compounds is given. Analogous 

 chlorides were found to be incapable of preparation in presence of 

 water, but the corresponding potassium and ammonium selenium 



