150
Reviews
volume is a minimuin for constant pressure and temperature, wliicli is certainly not true. The author further deduces Valson’s law of the nioduli, ostensibly without use of the electrolytic dissociatioii hypothesis, though, as a matter of fact, he postulates the acid and basic radicals as independent constituents.’ 1v.D. L’. The combination of sulphur dioxide and oxygen. E. J . R m s c l l and A? Smith. Jour. Chem. SOC.77, 340 (rgno).-The following coiiclusioiis were drawn : I. \Vlien a mixture of sulphur dioxide and oxygen is allowed to stand over certain metallic oxides at the ordiiiary temperature, conil~inationtakes place to a certain extent between the two gases, owing to the “ surface action ” exerted by the metallic oxide. 2. I f i t h the same oxide, the amount of the sulphur trioxide formed depends on the extent of the surface of the oxide. 3. With the same oxide, this amount clepends also on the state of the surface. I t appears to be least with freshly precipitated oxides which are not yet dried, and to increase if the oxide has been nioderately heated or kept for a long time so as to become dry. 4. The aniount appears to be absolutely depeiideiit on a simultaneous combination of the oxide with the sulphur dioxide, and in fact seems to proceed concurrently with this. . 5 . The most striking instance of this surface action is afforded by manganese peroxide, some twenty percent of the sulphur dioxide being converted into sulphur trioxide If the materials are carefully dried by mentis of phosphorus pentoxide, no combination takes place as, even after standing several days, no change in rolunie can be detected. By drying the mixture, combination of manganese dioxide and stilfur dioxide is thus prevented, as is also the surface action of the oxide wliicli brings about the unionof sulphur dioxide and oxygen. 6. \\’hen sulpliur dioxide and oxygen are p a d over heated platinized pumice, combination diminishes as the materials are more cotiipletely dried, and can be made very small. 1v. D. 6.
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Influence of the nascenf state on the combination of dry carbon monoxide and 7 7 , 3 6 r (rpoo).-Pure carbonyl suloxygen. E . J . Russell. Jour-. Chern. SOC. phide will not explode if sparked with oxygen. With a small amount of mipurity, some carbonyl sulphide is decomposed into carbon monoxide and sulphur, witliout these substances reacting with the excess of oxygen. The same thing is true of mixtures of carbonyl sulphide and nitrous oxide. The state of affairs following 011 a violent reaction - such as explosion of carbon disulphide or chlorine monoxide- has a considerable influence in bringing about a combination of carbon monoxide and oxygen, but there is no satisfactory proof that nascent carbon monoxide differs appreciably from the ordinary gas. UT.D. B. The decomposition of chlorates. U’. H. Sodenu. Jour. Ckem. SOC. 77, r.37, 77 ‘ (r9ao). -The author’s experiments are explained by him on the assumption of two independent reactions, the evolution of oxygen, and the evolution chlorine and oxygen. With potassium chlorate there are only traces of
Revie ius
1.51
chlorine set free ; in the slow decomposition of barium chlorate, the arnoant of free chlorine is less than one-tliousandtli of tlie chlorine in the salt. With lead chlorate the decomposition-products are lead chloride, lead peroxide, oxygetl and chlorine ; about eighty-seven percent of the chlorine is set free. 1V. D.B.
The persulphuric acids. T. X . L o w ) y n n d j . 1% ll'cst. JOUT-. Chem. soc. authors have determined the amount of persulphuric acid fornied when hydrogen peroxide is added to sulphuric acids of varying concentrations. If we assume that the mass law applies, without corrections for electrolytic dissociation, the results poiiit to the existence of pertetrasulphuric acid, EI,S,O,,. 1v.D. B. 7 7 , 950 (1900).-The
The reducing action of calcium carbide. Geelmuyden. Comftes rendus, (1900).- At the temperature of the electric furnace, calcium carbide reduces iron pyrites, galena, magnesium sulphide, and antitrioiiy sulphide to the metal ; aluminum sulphide is not reduced ; boric anhydride is converted 1v.D. 0. into calcium boride. 130,1026
Preparation of the phosphides of iron, nickel, cobalt, and chromium. 1. iVaronnenx. Comfii'es il-endus, 130, 657 (zpoo). -The phosphides of iron, nickel, cobalt, and clironiiuni have been prepared by heating the metal in question in the electric fiirnace together with the phosphide of copper. W. D.B. The separation of the rare earths. R.Chavustelon. Coiuptes rendus, 130, 781 (IF). - The author precipitates everything except tlioriurn by means of an alkaline sulphite, or else he gets the thorium and cerium alone in solution by 1V. D. B. the action of bicarbonates on the mixed oxides. A new method of fractioning some of the rare earths. E. Demarqay. Covififesrendus, 130, zor9 (z9oo).-The method consists in the fractional crgstallization of the double magnesium nitrates in nitric acid. 1 . . D. B.
Velocities
On the velocity of solidiiication and viscosity of supercooled liquids. H.A. Wilson. Phil. Mag. [ 51 5 0 , 238 11900). -Considering the expression which the author previonsly obtained to represent the velocity of solidification (3,423), if F, the latent heat of fusion of one gram of the solid, R , the thickness of tlie surface of separation of liquid and solid, and A, the force required to give unit velocity to one gram of the liquid diffusing through itself, be all regarded as constant, then v = c - ,S
v
where C is a coiistant, S is the actual supercooling, and V is the viscosity of the liquid. The present paper contains experimental data taken to test this formula. The substances chosen were salol, benzoic anhydride, benmphenone, and azobenzene. The results show that the velocity of solidification of a pure substance varies directly as the actual supercooling at which solidification occurs, and inversely as the viscosity of the liquid. H. T. B.
