

^5. 



1877] 



NATURE 



283 



bromide is attacked by antimony pentachloride, the whole of the 

 bromine being liberated and ethyle chloride formed. The action 

 of antimony pentachloride on ethene bromide differs according to 

 the quantities employed. With the same number of molecules of 

 the two substances the chief product is ethylene chlorobromide, 

 whilst with two molecules of pentachloride to one of ethene 

 bromide the product is ethene chloride. Ethene bromide is not 

 acted on when similarly heated with phosphorous pentachloride. 

 The product of the reaction of ac2lic acid with antimony pentachlo- 

 ride is monochloracetic acid, accompanied by another substance 

 with a higher boiling point. When salicylic acid is gradually 

 added to antimony pentachloride, monochloro- and dichloro-sali- 

 cylic acids are produced along with other products ; monocbloro- 

 salicylic acid is found in small quantities only. Dichloro-salicylic 

 acid on being boiled with potash for a considerable length of time 

 exchanges its chlorine for hydroxyl, yielding gallic acid accom- 

 panied with pyro-gallic and oxy-salicylic acids. When para- 

 oxybenzoic acid is acted on by two or four molecules of antimony 

 pentachloride the mono- and dichlorinated acids are found re- 

 spectively. From these reactions it is evident that the action of 

 antimony pentachloride differs from that of its analogue, phos- 

 phorous pentachloride, since it simply parts with its chlorine, 

 which replaces hydrogen in the acid radical, instead of replacing 

 the hydroxyl group by chlorine, as is generally the case when 

 phosphorous pentachloride acts upon organic substances. 



Action of Chlorine on Peroxydes. — MM. Spring and 

 Arisqueta continue {Bull. Acad, de Belg., xlii. p. 565) their 

 researches into the action of chlorine on peroxydes of metals, for 

 the purpose of elucidating the very important question whether 

 the atomicity of certain bodies is variable (as supposed by Kolbe 

 and Blomstrand), i.e., whether whilst one atom of a body in a 

 molecule is, say, tri-atomic and possesses basic properties, another 

 atom of the same body may be pent-atomic and partake of the 

 properties of an acid, or whether the atomicity remains invariable, 

 as supposed by Kekule and the authors of the paper. Former 

 researches induced M. Spring to conclude that the atoms of chlo- 

 rine possess constantly the same properties in all their compounds 

 with oxygen, which would be contrary to the alleged varying 

 atomicity. Now, studying the action of chlorine upon the per- 

 oxyde of silver, the authors prove, by a very delicate experiment, 

 that its result is the formation of a peroxyde of chlorine, a body 

 prevised by the theory, but unknown until now, and they conclude, 

 therefore, that the structure of peroxydes of silver and of chlorine 

 is identical, which identity gives a new argument in support of 

 the invariability of the atomicity of chlorine and silver. 



Boron and its Specific Heat. — Boron occurs, it is 

 known, in two different forms, in the amorphous state, and in 

 crystals. M. Hampe has recently found {Liebig^s Aiinalen der 

 Chemie) that both the black and the honey-yellow crystals are 

 not pure boron, but compounds of the element ; the black 

 crystals consisting of albuminium and bromine in the proportions 

 AlBjo, and the yellow crystals of aluminium, carbon, and boron, 

 CjAlgBig. Boron has hitherto been numbered among the few 

 elements which show a departure from Dulong and Petit's general 

 law of the constancy of specific heat into atomic weight, and M. 

 Weber sought the reason for this departure in the case of boron, 

 as in those'Tf carbon and silicon, in the fact that the specific 

 heat varies with the temperatures, but at high temperatures 

 reaches a value which establishes an agreement with Dulong and 

 Petit's law. The determination of the specific heat of boron, 

 however, as also M. Weber's experiments, were made with 

 crystals of boron. Now, since, according to M. Hampe, these 

 crystals are not pure boron, but compounds of it, the whole 

 question as to the validity of Dulong and Petit's law for the pure 

 element boron remains an open one. All the attempts made by 

 ^I. Hampe to produce pure crj-stallised boron had been with- 



out success. He is engaged in further investigating whether the 

 amorphous boron can be produced in absolute purity. 



Heated Air. — Dr. Kayser, of Nuremberg, has lately con- 

 ducted a number of experiments upon the effects of heating 

 ordinary air, with especial reference to the warming of dwellings. 

 The results appear in the last report of the Munich Industrial 

 Museum, and may briefly be summed up as follows : — Air 

 previously free from carbon monoxide was invariably found to 

 contain this gas after heating. The tests were performed with 

 chromic acid, and also with cuprous chloride. In order to test the 

 products of the decomposition of the dust present in the air, about 

 sixty litres of air, which had been heated, were drawn through 

 an ordinary apparatus for determining carbonic acid, which con- 

 tained absolute alcohol. The liquid assumed a yellowish brown 

 colour, and flakey masses were suspended in it. The flakes were 

 found to consist chiefly of carbon. After filtration and evapora- 

 tion of the solution, a brown residue was obtained. This was 

 insoluble in water, intensely acrid, and possessed a resinous, em- 

 pyreumatic odour. The estimations of carbonic acid and water 

 before and after heating showed no difference worthy of 

 mention. 



NOTES 

 Contributions are being collected in Stockholm for the 

 establishment of a scientific college. The Da^blatt states that 

 steps will be taken at once to fill the chairs in philology, the 

 natural sciences, history, &c. 



Baron von Richthofen, for a long series of years president 

 of the Berlin Geographical Society, has accepted a call to the 

 Chair of Geography in the University of Bonn. 



The large collections brought back by the German exploring 

 expedition in the Gazelle under the command of Baron v. 

 Schleinitz have been formed into a separate museum in Berlin. 

 The ethnographical section is especially rich and valuable, em- 

 bracing many objects brought from islands where the natives are 

 rapidly disappearing. 



The Society for African Exploration at Berlin has been 

 amalgamated with the newly-formed German branch of the 

 international societies, under the leadership of the King of 

 Belgium. During the three years of its existence it has been 

 exceedingly active, and has expended the following sums : — Dr. 

 Giissfcldt's Loango expedition, 9,200/. ; expedition of Homeyer, 

 Lux, and Pogge to the Cassandje, 1,000/. ; Dr. Lenz's journey 

 to the Ogowe, 1,000/. ; various stations and shorter excur- 

 sions, 2,500/. It has at present over 5,000/. in its treasury. 

 The first session of the newly-formed Deutsche afrikanische 

 Gesellschaft, was held in Berlin on January 16. The society 

 confines its field of operations to Central Africa, proposing to 

 open up this region "to civihsation, travel, and commerce, by 

 the establishment of permanent stations and the maintenance of 

 exploring parties." The energies of the society will also be 

 directed to the repression of slavery. A letter was read from 

 the Crown Prince of Germany, expressing his desire to take an 

 active part in furthering the objects of the Society. A request 

 for pecuniary assistance from the Government has already been 

 presented to the Chancellor of the Empire. 



The Berlin Afrikanische Gesellschaft has received telegraphic 

 news from Dr. v. Pogge, the African explorer, who landed last 

 week in Lisbon, stating that he had succeeded in penetrating to 

 the long-sought-for country of King Muata Yambo in Central 

 Africa. A detailed report is awaited with interest in geographical 

 circles. 



Dr. O. Lenz, the African traveller, has been forced to return 

 to Europe with a shattered constitution. For a number of years 



