86 



CHEMISTRY. (CHEMICAL ANALYSIS.) 



the solubility of which appears to be much the same 

 as that of "the India-rubber hydrocarbon itself. 

 The oxygen addition products contained in it do 

 not appear sensibly to affect the chemical behavior 

 of the whole. A high molecular weight is thus 

 indicated. The composition of a chlorine com- 

 pound obtained by Gladstone and Hibbert is in 

 agreement with their conclusion that the hydro- 

 carbon has for C 10 H 1(I three pairs of doubly linked 

 atoms. Accordingly, India rubber (polyprene) 

 must be an olefinic, and can not be a cyclic com- 

 pound like the ordinary terpenes. In other words, 

 the constitution of polyprene would be that of an 

 olefinic polyprene, standing at the end of the ter- 

 pene series, just as the ordinary polyprenes stand 

 at the end of the cycloterpenes the hemiterpene 

 C 5 H 8 isoprene representing the connecting link 

 between the two series. 



A method proposed by Carl Otto Weber for sepa- 

 rating India rubber from the mineral matter it 

 contains by boiling finely divided rubber in a 

 flask fitted with a vertical condenser with nitro- 

 benzine, has given very satisfactory results in the 

 author's practice. The only drawback to it is 

 represented to be the difficulty sometimes experi- 

 enced in eliminating the mineral matter from the 

 solution of the products of decomposition of the 

 India rubber. The author's experiments are con- 

 tinued on this and other points in the analysis. 



A number of analytical methods applicable to 

 the treatment of manufactured India rubber, pub- 

 lished by Dr. R. Henriques, give processes for the 

 estimation of the total sulphur and mineral con- 

 stituents; of factitious matter in vulcanized India 

 rubber; of nonsaponifiable oils in vulcanized mix- 

 tures; of factitious matter and of nonsaponifiable 

 oils in nonvulcanized India rubbers; and of car- 

 bonic acid. The author says he has not, on many 

 occasions, been able to obtain satisfactory results 

 when following the method proposed by Weber, 

 either in its original or in its improved form. Non- 

 vulcanized or slightly vulcanized rubber, it is true, 

 dissolves in boiling nitrobenzine, but if we have to 

 deal with hard or highly charged rubbers it is very 

 difficult to dissolve the whole of the gum, and the 

 filtration of the residue presents insurmountable 

 difficulties. 



Armand Gauthier concludes from the researches 

 he has made that pure air contains normally about 

 nrftrnr of its volume of free hydrogen, to which 

 must be added, owing to the exhalations and fer- 

 mentations of the soil, vegetables, animals, and 

 products of human industries, a certain proportion 

 of hydrocarbons, which is relatively great in popu- 

 lous towns, small in country districts, very slight 

 on rocky plateaus and peaks of high mountains, 

 and particularly absent in the higher regions of 

 the atmosphere. There will remain to be deter- 

 mined the nature of the hydrocarbons of the air 

 of towns and woods and the origin of atmospheric 

 dryness. 



A method of estimating halogen elements in 

 organic compounds by combustion in a calorific 

 bomb is described by M. A. Valeur, who finds it 

 eminently practicable by reason of the complete 

 and instantaneous combustion of the substance 

 and the rapidity of the operations. 



The report of the British Government Labora- 

 tory records the examination of a number of 

 tinned meats which had been furnished by the 

 Admiralty for the detection of food preservatives. 

 No antiseptic other than common salt was found. 

 Numerous butters contained boric preservatives, 

 and were artificially colored. The use of boric 

 acid is most prevalent in butters from France, 

 Belgium, and Australia, and is very common also 

 in Holland. The most frequent coloring matter 



is annotto, but the use of coal-tar yellows is on the 

 increase, and is especially prevalent in the United 

 States, Holland, and Australia. A filter for pas- 

 senger ships capable of freeing water from micro- 

 organisms had been constructed at the laboratory. 

 An investigation had been undertaken into the 

 mode in which phosphorus in steel is chemically 

 combined, from which it was shown that that 

 substance, like the carbon, is not unfrequently 

 present in more than one form of combination. 

 Another investigation was directed to lead poi- 

 soning from the use of lead compounds in pot- 

 tery manufacture. A considerable number of 

 " fritts " and " glazes " had been examined, and 

 the conditions determining the ease with which 

 lead compounds may be extracted from them by 

 dilute acids comparable as regards their action 

 with that of the gastric juice and other animal 

 solvents had been ascertained. As a result of the 

 inquiry, the Home Secretary has requested the 

 manufacturers of pottery to abandon the use of 

 raw lead ; and in view of the facts brought to light 

 by the examination of the fritts and glazes, he 

 has expressed the intention of prescribing that in 

 future such glazes shall conform to a standard 

 of insolubility as regards lead. 



Besides a paper on The presence of Fluorine in 

 the Mineral Waters of Spain and Portugal, a pre- 

 liminary account of researches on the subject has 

 been published by A. J. Ferreira da Silva and 

 Alberto d'Aguilar. M. Parmentier mentioned the 

 presence of fluorine in considerable quantities in 

 the waters of the springs of Gerez. M. Ricardo 

 Jorge regards these waters as the most fluorized 

 waters in Europe, and estimates that they contain 

 four times as much fluorine as those of Carlsbad. 

 This author has tabulated, from this point of view, 

 the values of other similar springs in Europe, and 

 has further shown by experimental research the 

 therapeutic action of the alkaline fluorides, thus 

 clearing up the mystery which enveloped the salu- 

 tary action of these waters. One oi the authors 

 of the paper now under consideration found in the 

 spring at Campilho, at Vidago, fluorine in much 

 greater quantity than it had been found in other 

 springs in northern Portugal. Dr. Casares Gil has 

 found fluorine in quantities corresponding, but a 

 little exceeding, that found at Gerez. He believes 

 that fluorine is to be found in many mineral waters 

 in much higher proportions than has been ob- 

 served up to the present, and that for this reason 

 many analyses should be revised. He suggests thai 

 the reasons fluorine has not been more generally 

 detected in springs are because it has not been 

 carefully looked for, and because the action of 

 hydrofluoric acid on the glass has been chiefly re- 

 lied upon as the test, while in the usual method 

 of analysis by treatment with concentrated sul- 

 phuric acid, not hydrofluoric acid is given off, but 

 fluoride of silicon, the action of which on glass is 

 barely noticeable. 



A specimen of soot from an ordinary household 

 chimney in Birmingham, England, analyzed by 

 H. Worth, yielded totals of 7.4 per cent, of am- 

 monium salts and 1.3 per cent, of fixed soluble salts. 

 The fixed salts consisted of sulphates and chlorides 

 of sodium, magnesium, calcium, and iron more 

 sulphates than chlorides (3 to 1). This circum 

 stance explains the almost total absence of sul- 

 phates among the volatile portion. The sulphur 

 trioxide was chiefly retained by the nonvolatile 

 metals, and thus it is that the volatile portion 

 consists of nearly pure ammonium chloride. The 

 proportion of ammonium salt in the soot is large 

 enough to justify the esteem in which soot is held 

 as a plant manure. 



A reaction of cotton-seed oil, described by S. A. 



