

CHEMISTRY. (ATOMIC WEIGHTS.) 



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in a very ingenious way by a process devised by 

 Ilargreaves and Bird, and in another process by 

 Hulin, which is similar to it. When mercury is 

 employed as the cathode the diaphragm becomes 

 unnecessary, the mercury taking up sodium in con- 

 tact with the salt solution and giving it up to pure 

 water in another vessel. Several devices have been 

 contrived for causing the mercury to perform these 

 functions alternately, among which one by Mr. 

 Castner is described by Mr. Thomas Ewan as being 

 the most effective. The caustic soda obtained in 

 this way is practically pure. If instead of keeping 

 the products of the electrolysis of a salt solution 

 separate they are mixed together in the cold, a solu- 

 tion of hypochlorite is formed. 



Of two methods described by M. Moissan by which 

 crystalline calcium may be prepared containing 

 less than 1 per cent, of impurities, one depends 

 upon the property possessed by calcium of dissolv- 

 ing in liquid sodium at a dull- red heat and separat- 

 ing in crystals on cooling. By treating the mass 

 'cautiously with absolute alcohol the sodium is re- 

 moved and the calcium is obtained in brilliant 

 white hexagonal crystals. In the other method 

 similar white crystals of calcium are obtained by 

 the electrolysis of fused calcium iodide. Calcium 

 has been described by previous workers as a yellow 

 metal, but in the light of M. Moissan's experiments 

 that color was probably communicated by im- 

 purities. 



Considering the production of volatile fatty acids 

 from the washing waters of wool as now of practical 

 importance, A. and P. Buisine give an abstract of 

 the method of procedure by which the acids are dis- 

 tilled and entangled with watery vapor and con- 

 densed by it. The waters are first allowed to 

 ferment for eight days, then boiled to drive off the 

 ammonia, then acidulated with sulphuric acid and 

 distilled. The volatile fatty acids found in the lar- 

 gest quantities are acetic and propionic, but we also 

 get a fair percentage of butyric, valerianic, caproic, 

 and benzoic acids, with traces of formic and caprilic 

 acids and phenol. Among other applications, this 

 mixture of raw fatty acids is particularly suitable 

 for the production of acetone, methyl-ethylacetone, 

 and the higher acetones comprised by the mixture 

 known as " oil of acetone." 



In the commercial extraction of thorium by M. 

 Wyronhoff and A. Verneuil the mineral is worked 

 up by one of the usual methods as far as the pro- 

 duction of the oxalates ; these are precipitated by 

 sodium carbonate and hydroxide, and the precipi- 

 tate is dissolved in hydrochloric acid. This liquid 

 is treated with small portions of barium peroxide 

 until hydrogen peroxide no longer gives a precip- 

 itate. The deposit, which is of a reddish-orange 

 color owing to the presence of cerium, contains all 

 the thoria, together with from about 20 to 30 per 

 cent, of impurities. Further treatment with hydro- 

 gen peroxide after a similar set of operations 

 readily gives a very pure thoria. The method has 

 been applied on the large scale, starting with five 

 tons of monazite. with good results. 



Bite's boiling-point apparatus is described by 

 H. C. Jones as one in which the condensed solvent 

 is not returned directly into the boiling solution. 

 It consists of a tube about one fourth filled with 

 glass beads, on which rests a platinum cylinder. 

 The thermometer is immersed in the solvent inside 

 the cylinder which serves to separate the condensed 

 solvent and the boiling solution. 



J. Hausser has found that of all the substances 

 he has tried for the purification of water by filtra- 

 tion, the infusorial earth called Kieselguhr has 

 given the best results. It is prepared by first finely 

 sifting to remove all large particles, and then heat- 

 ing to about 800 or 1,000 C. On cooling, it must 



be pulverized and levigated to obtain an impal- 

 pable powder though this last operation is not 

 necessary in the case of all the substances dealt 

 with. To use it, the powder is mixed with a little 

 water and thrown on a filter ; as the liquid passes 

 through, the powder remains, and forms a perfect 

 layer for filtration and sterilization. 



Having prepared cuprous iodide by one of the 

 usual methods or by sprinkling iodoform in small 

 quantities at a time upon a hot surface of copper, 

 Bevan Lean and W. H. Wheatmough most conven- 

 iently separate iodine from it by heating in a 

 stream of dry air at from 220 to 240 C. and con- 

 densing the vapors upon a cold surface. But al- 

 though the greater proportion of the iodine in a 

 given quantity of cuprous iodide is quickly ex- 

 pelled, it is not easy to expel the whole, and the 

 authors are making further experiments upon this 

 point. The action of air on cuprous iodide is 

 shown not to be dependent upon the presence of 

 moisture. Iodine liberated as described from 

 cuprous iodide at 240 C. leaves no residue when 

 volatalized at 75 C. If examined spectroscopic- 

 ally, no evidence of the presence of copper can be 

 found. The melting point uncorrected is from 

 112.5 C. to 114 C. 



In M. R. Metzner's process for preparing selenic 

 acid with copper selenate, selenium is converted 

 into selenious acid, and this is oxidized in solution 

 with chlorine. Copper oxide is added to this 

 liquid and evaporation gives fine prisms of copper 

 selenate. Pure selenic acid is obtained from this 

 by electrolysis. 



Atomic Weights. The variations in determina- 

 tions of the atomic weights of nickel and cobalt 

 have led to suggestions that these metals contained 

 another new element, for which Kriiss offered the 

 name of gnornium. The results of analyses of the 

 two metals by Richards and Cushmanandby Rich- 

 ards and Baxter fail to confirm this supposition, 

 and demonstrate that properly purified nickel and 

 cobalt are homogeneous. Analyses of the bromides 

 of the two substances gave as the identical values 

 of their respective atomic weights, from 3 deter- 

 minations each, for nickel, 58.69, and for cobalt, 

 58.99 ; O = 16. 



A theory of valency is explained by Dr. Joachim 

 Sperber which presumes the existence of elements 

 that can not erfter into chemical combination be- 

 cause their atoms have a prevailing tendency to 

 transverse vibrations ; there is, too, the author sug- 

 gests, substantial proof of this, for the cosmic ether 

 is without doubt such an element, since it does not 

 enter into chemical combination, and its vibrations 

 are transversal. Moreover, the chemically negative 

 elements argon and helium have recently been 

 discovered, and if they can not be made to enter 

 into chemical combination as up to the present 

 time is the case this, in accordance with the 

 author's theory of valency, is to be attributed to a 

 prevailing tendency on the part of their atoms to 

 vibrate transversely. Julius Thomsen supposes 

 that if the chemical character of the element is 

 altogether a periodic function of the atomic weights, 

 such a function must also obey their general laws. 

 The periodic functions the transition from neg- 

 ative to positive values, and inversely must take 

 place either by way of zero or of infinity ; in the 

 former case the transition is gradual, but in the 

 latter case sudden. The former case corresponds 

 to the gradual modification of the electrical char- 

 acter with the increasing atomic weight in the in- 

 dividual series of elements ; but the latter case cor- 

 responds to that of the transit from one series to 

 the next. Hence it may be supposed that the 

 transit from one series of elements of the periodic 

 system to the next takes place by way of an ele- 



