574 



NA TURE 



[October 4, 1906 



at the renovated Charing Cross Station, as they found by 

 test that, on the price for price basis, the oriflame lamps 

 gave a much better light than the high-pressure gas lamps. 

 Mr. Andrews's paper chiefly deals with one particular kind 

 of flame arc lamp, namely, the Carbone lamp. The paper 

 led, however, to a discussion which opened up the question 

 in its more general form. It is to be hoped, therefore, that 

 the question of long-flame arcs will not be allowed to 

 drop until a much greater development has taken place, 

 as much is needed before we can say that it is perfect, as 

 the efficiency of flame arc lamps still leaves much to be 

 desired. 



The August issue of the Psychological Bidleiin is a 

 pathological number. In addition to an article on the re- 

 lation of emotional and intellectual functions in paranoia 

 and in obsessions (by Dr. Adolf Meyer, the editor of this 

 number), it contains a discussion by Dr. J. W. Baird of the 

 contraction of the colour zones in hysteria and in neuras- 

 thenia. The conclusions to which Dr. Baird's observations 

 lead are (i) that the colour zones of the abnormal sub- 

 jects examined are, on the whole, of smaller area than 

 those of the normal subjects, and (2) wherever a contrac- 

 tion of the colour zones occurs a definite order is observed 

 — the red and green zones narrow together and the blue 

 and yellow zones together, and there is a greater degree of 

 contraction in the red-green zone than in the blue-yellow 

 zone. 



Although it is well established that selenium and 

 tellurium are isomorphous in their compounds, it is still 

 a question of controversy whether the isomorphism extends 

 to the substances in the elementary state. Drs. G. Pellini 

 and G. Vio show in the Atti dei Lincei (vol. .xxv., ii., 

 p. 46) that the solidifying points of mixtures of these sub- 

 stances are proportional to the percentage compositions, 

 and that the elements are therefore isomorphous. The 

 hexagonal mineral tellurium from Honduras, which con- 

 tains about 29 per cent, of scleniuin, would thus appear 

 to be an isomorphous mixture. 



A METHOD of isolating radio-thorium from thorium salts 

 is described by Messrs. G. A. Blanc and O. Angelucci in 

 the Atti dci Lincei (vol. xxv., ii., p. go). When sulphuric 

 acid is added to a solution of thorium nitrate containing 

 barium chloride no precipitate is formed in the cold solu- 

 tion, but on warming, part of the barium is precipitated 

 as sulphate, the precipitate carrying down some of the 

 radio-thorium. The sulphate is converted into carbonate 

 by fusion with sodium carbonate, and the product, after 

 thorough washing, is dissolved in acid ; on adding ammonia 

 a slight precipitate of radio-thorium is obtained which has 

 an activity about 5000 times as great as thorium hydroxide 

 in a state of radio-active equilibrium. 



The use by the Kbnigliche Porzellan Manufactur of 

 fused magnesium oxide in the construction of tubes and 

 crucibles has led Messrs. H. M. Goodwin and R. D. 

 Mailey to publish the results they have obtained in an 

 investigation of the physical properties of fused magnesium 

 oxide {Physical Review, vol. xxiii.. No. i). The fused 

 substance is a white, very hard crystalline substance, the 

 size of the crystals depending on the rate of cooling. The 

 melting point of the material is 1910°, the coefficient of 

 expansion being very nearly the same as that of platinum, 

 a fact which will prove of value in its application. The 

 results recorded for the electrical conductivity show that 

 up to 1150° C. fused magnesia is a better insulator than 

 porcelain. Fused salts, as a rule, have very little action 

 on the materia], and it is attacked only slowly by cold, 

 dilute mineral acids. 



NO. 1927, VOL. 74] 



In an article in No. S of Le Radium Mr. A. S. Eve 

 describes a method of estimating the proportion of radium 

 or thorium in a mineral by means of the 7 rays which it 

 emits. Incidentally, it is pointed out that solutions of 

 radium bromide which are intended to serve as standards 

 of radio-activity are liable, unless acidified, to become in- 

 exact owing to the deposition of radium on the glass of 

 the vessels containing them. It appears advisable always 

 to control such solutions by reference to a standard of 

 solid radium bromide. Dr. M. Levin contributes an article 

 on the absorption of the o rays of polonium to the same 

 number of Le Radium, Mr. H. L. Bronson deals with the 

 transformation periods of radium A, B, and C, and Mr. 

 W. H. Bragg describes investigations of the a particles of 

 uranium and thorium. 



Both theoretically and practically the formation of 

 " basic " salts has long been a difficulty to chemists. In 

 the case of the carbonates, for example, no good reason 

 has been given why the carbonates of the metals of the 

 alkaline earths alone should be definite compounds. The 

 current number of the Journal of the Society of Chemical 

 Industry contains an interesting study of the basic 

 carbonates of magnesium, by Mr. W. A. Davis, which 

 throws a good deal of light on these very obscure com- 

 pounds. The starting point of the work is magnesium 

 bicarbonate. It has been shown by Treadwell and Reuter 

 that whilst a solution of calcium bicarbonate is stable at 

 the ordinary temperature, a solution of the corresponding 

 magnesium compound is only stable in the presence of 

 carbon dioxide. It is known that when the pressure 

 of the carbon dioxide above this solution is removed 

 crystals are deposited of the composition MgC0,,.3H,0, 

 and these have been regarded as hydrated magnesium 

 carbonate. In the present paper the author shows that 

 this substance is really a hydroxy-carbonate, 

 Mg(OH)(C03H)2H,0, 



since only two-thirds of the water can be driven off at 

 100° C, or by boiling with xylene. Photomicrographs of 

 both these salts are given. The decomposition products of 

 this hydroxy-carbonate are then studied, and the results 

 applied to the softening of magnesian waters, the Solvay 

 method of manufacturing potassium carbonate with the aid 

 of magnesia, and the formation of mixed carbonates of 

 magnesium and the alkalis. The author claims that 

 various observations which were formerly inexplicable may 

 be interpreted without difficulty in the light of the explan- 

 ation which has been given of the manner in which basic 

 carbonates are formed. 



Prof. Str.4Sburger's interesting book on botanical and 

 other natural characteristics of the Riviera, a review of 

 which appeared in Natl're of June 22, 1905 (vol. Ixxii., 

 p. 171), has been translated into English by O. and B. 

 Comerford Casey, and is published, with the coloured 

 illustrations, by Mr. T. Fisher L'nwin. The English 

 version of this charming book will delight visitors to the 

 Riviera who are unfamiliar with the German language. 



A series of instructive experiments in practical photo- 

 graphy is described by Mr. T. T. Baker in a booklet 

 entitled "Simple Photographic Experiments," just pub- 

 lished by Messrs. Percival Marshall and Co. 



Messrs. Constadle and Co., Ltd., have just published 

 the third edition of Mr. H. H. Cunynghame's work " On 

 the Theory and Practice of .\rt-enamelling upon Metals." 

 A short description of a new furnace invented by the 

 author has been added to the volume. 



