CHEMISTRY. 



117 



ment of microbes, exerts only a very feeble 

 disinfectant action upon tbe products of putre- 

 faction. There is likewise no parallelism be- 

 tween the power of preventing putrefaction 

 and that of checking it when it has begun. 

 Phenol and alcohol are excellent preservative 

 agents, bnt have only a slight action upon 

 putrefaction in progress ; with the exception 

 of a very few substances which are powerful 

 toxic agents, such as mercuric chloride, the 

 greater number of antiseptics, and notably 

 phenol, have only a very feeble action upon 

 bacteria. M. Le Bon even regards phenol as 

 one of the best liquids which can be employed 

 to preserve living bacteria for a long time. 

 The experiments made upon cadaver alkaloids 

 can not serve to decide the question as to 

 whether the volatile alkaloids which give to 

 putrefaction its odor are poisonous, for such 

 experiments have generally been made by in- 

 troducing into the system putrefaction prod- 

 ucts containing bacteria, to which the effects 

 observed may be attributable. M. Le Bon's ex- 

 periments were made upon frogs placed in jars, 

 at the bottom of which was a very thin layer 

 of his normal liquid. At the beginning of the 

 putrefaction the liquid, although it emitted a 

 very fetid odor, swarmed with bacteria, and 

 was very virulent if injected under the skin, 

 had no appreciable effect upon the frogs ; but 

 the same liquid, two months old and no longer 

 having virulent properties, killed in a few min- 

 utes the animals that breathed its exhalations. 

 In fact, the virulent power of a body in putre- 

 faction and the toxic power of the volatile 

 compounds which it gives off seem to be in an 

 inverse ratio to each other. The extremely 

 minute quantity of the products of advanced 

 putrefaction necessary to kill an animal by 

 simple mixture with the air it breathes is a 

 fact that shows these volatile alkaloids to be 

 extremely poisonous. 



Atomic Weights. Nilson has calculated the 

 atomic weight of thorium from the sulphate, 

 which he obtained from Arendal thorite by 

 successive treatment with hydrochloric and 

 sulphuric acids. The purified salt was twice 

 precipitated with ammonia, and washed and 

 dissolved in hydrochloric acid, and then con- 

 verted into an oxalate ana ignited. The snow- 

 white oxide was converted into sulphate, and 

 this was allowed to crystallize by the sponta- 

 neous evaporation of its solution. Large, trans- 

 parent, brilliant crystals were thus obtained, 

 which were permanent in the air and had the 

 composition Th(SO 4 ) 2 (H 2 0). For the estima- 

 tion of the atomic weight a weighed quan- 

 tity of the pulverized salt was heated to expel 

 its crystal water, again weighed, and then 

 again heated to a full white heat. The sul- 

 phuric oxide was entirely expelled, leaving the 

 pure thorium oxide, which was again weighed. 

 From the data thus obtained the atomic weight 

 was calculated. Assuming the quadrivalence 

 of thorium, the means of two series of obser- 

 vations are, respectively, 232-43 and 232*37. 



Cleve, taking the mean of twelve experi- 

 ments upon the synthesis of yttrium sulphate 

 with pure material, proved to be free from 

 terbia, has redetermined the atomic weight of 

 yttrium to be 88'9'027, or, if SO 8 =80, then 

 Yt=89'02. The last figure suggests a fairly 

 close conformity with Prout's law. 



Clemens Zimmermann has prepared uranium 

 by reducing a mixture of potassium or sodium 

 with chloride of uranium, by heating in a char- 

 coal crucible. Thus prepared, its atomic weight 

 has been calculated to be 240, or greater than 

 that of any other known metal. Uranium has 

 the color and luster of silver, but is harder, and 

 gives out sparks when struck with a hammer. 

 It oxidizes gradually when exposed to the air, 

 burns when heated on platinum-foil, and is dis- 

 solved by nitric acid. Its specific gravity has 

 been determined at 18'7. 



Analytic Chemistry. The properties of hydro- 

 gen dioxide as an oxidizing agent have been 

 found useful in a variety of analyses. It oxi- 

 dizes arsenious acid to arsenic acid, and phos- 

 phorous acid to phosphoric acid, and decom- 

 poses hydrogen sulphide with the formation of 

 water and free sulphur. If, however, it acts 

 in ammoniacal solution, such as ammonium 

 sulphide or sodium sulphide, the liquid be- 

 comes warm, and is gradually decolorized with- 

 out deposition of sulphur ; but that sub- 

 stance is instead oxidized to sulphates and hy- 

 posulphates. With sulphide of tin, antimo- 

 nium and arsenic in ammonium sulphide, the 

 addition of hydrogen dioxide causes oxidation 

 of the ammonium sulphide, with at first pre- 

 cipitation of the other sulphides, ending, on the 

 addition of an excess of the reagent and heat- 

 ing, in their more or less complete transforma- 

 tion into oxides. The conduct of hydrogen di- 

 oxide toward ammonium sulphide, or the action 

 of hydrogen sulphide gas on ammoniacal hy- 

 drogen dioxide, maybe employed in qualitative 

 analysis for destroying an excess of those sul- 

 phides, and in quantitative analysis for deter- 

 mining amounts of gaseous or dissolved hydro- 

 gen sulphide, or for the determination of sulphur 

 or metals in sulphides. The property of oxi- 

 dizing hydrogen sulphide easily and completely 

 in alkaline solution may be taken advantage 

 of in the estimation of chlorine, bromine, and 

 iodine in liquids containing hydrogen sulphide. 

 Metallic sulphides which are oxidized directly 

 by hydrogen dioxide may be estimated by the 

 amount of sulphuric acid formed in the solu- 

 tion. Such metals are arsenic, antimony, zinc, 



copper, and cobalt. The estimation of metala 

 by this means is capable of more extended ap- 

 plication than the direct oxidation of the sul- 



phide. Pure metallic sulphides are seldom 

 obtained in analysis, but more frequently mix- 

 tures with free sulphur. The amount of free 

 sulphur does not affect the quantity of hydro- 

 gen sulphide liberated by an acid, and hence 

 the advantage of determining the latter. It is 

 absorbed in a peculiar apparatus, described by 

 the authors. Foremost among the metals that 



