July 28, 1 881] 



NATURE 



293 



half as weak again. Consequently the smallest possible effective 

 light for the formation of chlorophyll is attained by intermittent 

 illumination. During the formation of chlorophyll light is 

 bupplied in superabundance by a continued illumination in the 

 same manner as at the heliotropic bendings. 



A French physiologist, M. Gley, has made some delicate 

 exptriments on himself with regard to the effects of attention 

 and intellectual work on cerebral circulation. His results confirm 

 those of M. Mosso, and he has added some new observations. 

 He finds that the rhythm of the heart through intellectual work 

 is slightly accelerated ; and this increase seems in direct ratio 

 of the intensity of the attention. Thus the pulse was more 

 frequent when the author studied geometry, with which 

 he had little familiarity, than when he studied philosophy, 

 of which he had a ^^ood knowledge. While the heart-rhythm 

 is accelerated the carotid artery is dilated during cerebral work, 

 and the carotidian pulse becomes dicrotic. But the radial pulse 

 becomes smaller and less ample. The phenomena of congestion 

 observed in the brain persist a certain time after cerebral activity. 



CHEMICAL NOTES 



By the action of methylic iodide, in presence of sodium, on an 

 alcoholic solution of morphine, M. Grimaux has succeeded in 

 producing codeine, identical in properties with the naturally- 

 occurring alkaloid [Compt. rend.). If ethylic iodide is employed 

 in place of the methyl salt, a new alkaloid differing in composi- 

 tion from codeine by CIt„, is produced. M. Grimaux proposes 

 to call all the homologous bodies of this series codeines, and to 

 distinguish the commonly called codeine as codomethyline, the 

 new homologue as codethylitte. Sec. 



In Cazzetia C/dmica Italiana S. Valente describes a striking 

 lecture experiment illustrative of the fact that chlorine replaces 

 iodine from binary compounds. A jar, 500 c. c. capacity, is 

 filled with dry hydiiodic acid gas, and another, 250 c.c. capacity, 

 with dry chlorine, the jars being separated by a glass plate, and 

 the larger being uppermost ; on \\ ithdrawing the plate decom- 

 position of the hydriodic acid occurs with a ilash of rose-coloured 

 flame, and separation of iodine. 



SS. Bartoli and Papasogli claim to have prepared mellitic 

 and hydromellitic acids by the long-continued electrolysis of 

 water, using carbon electrodes (Nuovo Cemento). 



S. FuNARO describes two nickeliferous minerals from the 

 Apennines in the Gaz:etla Chim. Hal., to one of which he 

 gives the formula (FeNijjSg, and to the other the formula 

 CuaRj^Sb^Sj., where R = Cu : Fe : Ni = 3-4 : 4-2 : 2*4. 



In continuing his investigation of the action of hydrogen per- 

 oxide on aromatic compounds (Nature, vol. xxiv. p. iii) Dr. 

 A. R. Leeds shows that in some of ihese compounds the peroxide 

 acts only as an oxidiser, in other cases it replaces hydrogen by 

 (OH), and sometimes both actions occur together {Berliner 

 Berichte). 



The same chemist has repeated (Amer. Client. Journ.) many 

 of these experiments, wherein ozone is said to be produced by 

 the action of heat on metallic and non-metallic oxides ; he finds 

 that in every case the supposed ozone reaction, obtained by 

 bringing the evolved oxygen into contact v\ ith potassium iodide 

 and starth, is due to traces of impurities, generally to traces of 

 chlorine. 



According to M. Chappuis (Bull. Soc. Chim.) the phos- 

 phorescence of phosi'hoius in oxygen or air is an accompaniment 

 of the combustion of phosphorus vapour by ozone. Phosphorus 

 is not luminous in pure oxygen at 15°, and at the ordinary pres- 

 sure, introduction of a trace of ozone causes luminosity ; those 

 substances which hinder the luminosity of phosphorus, e.g. 

 turpentine oil, are substances which destroy ozone. If a little 

 turpentine oil is brought along with ] hosphorus into a tube con- 

 taining pure oxygen, and a small quantity of ozone is then 

 passed in, the phosphorus exhibits luminosity for a few moments 

 only ; M. Chappuis supposes that this is due to the combustion 

 of phosphorus vapiur by the ozone, and that the transiency of 

 the phenomenon is explained by the rapid removal of the ozone 

 by the turpentine oil. 



Experiments on the action of heat on oxides of manganese, 

 by S. V. Pickering, are detailed in Chem. Ncivs. According to 

 this chemist some specin.ens of manganese oxides undergo a slow 

 molecular change when kept. Thus a sample containing, when 



freshly prepared, 85"I49 per cent. MnO;, 9'3S6 percent. MnO, 

 and 5'490 per cent. H„0, lost i"o65 per cent, oxygen when 

 heated to 100°, but after eighty days the same sample gained 

 024 per cent. ox)gen when heated to 100°, and I 114 per cent. 

 at 195°. 



Herr E. Ramann concludes from his experiments {Berliner 

 Berichte) that the passivity of iron is always caused by the forma- 

 tion of a layer of magnetic oxide (Fe^Oj) on the s 'rface of the 

 iron. In addition to nitric acid, the follo%ving liquids induce 

 passivity in iron, viz. ammoniacal silver nitrate solution, solutions 

 of nitrate of silver, ammonium, aluminium, nickel, cobalt, or 

 iron. 



The same author describes an amalgam of iion, nearly of the 

 composition expressed by the formiJa HgjFe^, prepared by the 

 action of sodium-amalgam on finely-divided iron in presence of 

 water. Dry sodium-amalgam has no action on iron. 



Herren V. Mekz and W. Weith have investigated the 

 action of heat on various amalgams w ith the view of determining 

 whether these bodies lose mercliry regularly as temperature in- 

 creases, or whether they exhibit the properties of definite com- 

 pounds. The results, nhich are detailed in the Berliner Berichte, 

 seem to show that many amalgams, e.g. of gold, silver, copper, 

 bismuth, lead, cadmium, &c., although very easily decomposed 

 by hear, nevertheless contain their component elements in definite 

 proportions by weight ; such amalgams are probably to be classed 

 as molecular compounds. Amalgams of the alkali metals exhibit 

 the properties of definite compounds in a greater degree than 

 amalgams of the other metals. 



In the Berichte Herr V. Meyer publishes a note on the densities 

 of the vapours of the halogens, in which he states that he means 

 to relinquish the further working out of these problems to M. 

 Crafts. He states that he has oljtained numbers for the densities 

 of phosphorus and arsenic which stand midway between those 

 required by the formulae P4 and Asj, and P„ and Aso. 



Various papers on new nitrogen derivatives of carbon com- 

 pounds are published in the same Berichte, by Prof. V. Meyer 

 and his students ; these papers promise results of much interest. 

 Hitherto " azo-compounds " have only been known in the 

 aromatic series ; nitroso-substitution compounds of what is 

 apparently azo-ethane are described by Prof. Meyer, especially 

 NO-C,Hj— N2— C2H4— NO. A new series of organic bases 

 called " kelines" is also described. The starting-point of this 

 series is kdine or nitrosoacetene, CH3 — CO — CH.^(NO). 



Herr Strecker (Annalen Phys. Chem. ), from determinations 

 of the velocity of sound in chlorine, bromine, and iodine gases, 

 has obtained the follow ing numbers for the specific heats of the e 

 gases : — 



Chlorine. Bromine. Iodine. 



At constant pressure ... 0115 ... 005504 ... 003489 



At constant volume ... 00S373 ... 004257 ... 0-02697 



Ratio of values of the) ,. j.^g^ 



two specific heats ...)■'-' '•' 



From these re-ults it is concluded that the action and reaction 

 between the atoms in the molecules of these gases is different in 

 kind from that which subsists in otlier diatomic molecules, e.g. 

 oxygen or carbon monoxide. 



Remsen has again investigated the action of finely-divided 

 iron in inducing the formation of cyanide when nitrogen is 

 passed over a hot mixture of carbon, iron, and an alkaline metal ; 

 he finds {American Chem. Journ.) that freshly reduced iron 

 induces a large formation of cyanide, but that iron after keeping 

 for some time lo. es this power. 



From experiments on the decomposition of barium carbonate 

 by ammonium chloride solution, Tommasi (abstract in Berliner 

 Berichte) concludes that an aqueous solution of sal-ammoniac 

 contains free ammonia and free hydrochloric acid. 



Reference was recently made in these Notes to the experi- 

 ments of Jones on gasC' us boron hydride ; Reinitzer describes ex- 

 periments {Wien. Akad. Ber.) which appear to show that when 

 dilute hydrocldoric acid acts on potassium boride the solid green- 

 bron n amorphous powder w hich is formed is a boride of hydrogen 

 appro.\imately of the formula Bj^jH. 



Considerable doubt has been expressed whether calomel is 

 or is not liable to decomposition in the human system, with 

 production of corrosive sublimate. According to experiments 

 described by P. Hoglan {Chem. News) calomel is slow ly changed 



