T h e aqueous fusion of glass, its relation t o pressure and temperature. Cud 6 n r z s . Phil.-1faZ. 47, zog ( 1 8 9 9 . )--From a 3tucly of the compressibility of water in glass capillaries under high pressure and at a teniperature of 18s' C , the author finds that the absorption of glass by the mater m a y be expressed in about t h e proportion of 180 k g . per sq. meter per year. The absorption increases with temperature a n d , reasoning on t h e action of water on silicates in the earth, he concludes ' * t h a t the action of hot water on rock within t h e earth constitutes a furnace whose efficiency increases in marked H . 7:6. degree with t h e depth of t h e seat of reaction below sea-level." The absorption of water in hot glass. Crri-l ntrms. Phi/, Mng. 47, 461 1899). - .Ipplying pressure t o a thread of water in a capillary tube by means of a column of mercury, t h e temperature being maintained 1)y a vapor bath hetween I S j - and ZIO', the water passes through three stages : one of exparisioii to retain the ternperature of the rapor bath, one of great coniprewihility when t h e glass is being absorbed by t h e water which appears white and opaque, and one where. with increased pressure, the compressibility ceases atid t h e water becomes clear again. During t h e secoiid stage t h e v-ater does not act as an elastic medium, differing in this respect from the first atid third stages. T h e compressibility in t h e second stage may reach and exceed jocl J, IC-6. In t h e third stage, t h e water glass is a thick viscous fluid, which on cooling solidifies and is not directly distinguishable from igneous glass. From a thermodynamic 15'. 7.. C . point of vielv, two phases of \$-aterglass are supposed to esist. (
The specific gravity, refractive index, and content of solutions of sodium tungstate. Rr.P(z:ijlewski. Bel.. chei/z. e;s(. R C r l i i i , 33, r r y izpoo I . -.I table is given with t h e above properties of solutions ranging from 2-33 percent. c.G. L . IT'.
On the thermal conductivities of mixtures and their constituents. C'. H . Lees. Phi/. :1ITtrg. 49, 286 i 1 9 0 0 ) .-In t h e attempt to express the thermal conductivity of a mixture in terms of t h e conductivities of its constituents, two formulas hat-e been usually employed, which correspond, using either the masses or volumes of t h e constituents, to two different kinds of distribution. In one, the constituents are arranged as right pristns with axes perpendicular to two parallel isothermal surfaces through wliich t h e heat enters and leaves t h e medinm. I n t h e other, t h e axes of the prisms are parallel t o the isothermal surface. The author in a previous paper discusses a slightly different arrangement, wliich, when t h e constituents are equal. is capable of espressioti in a simple logarithmic formula. T h e case is that of a n equal number of infinit~lq-l o n g right prisms arranged end 011, hut parallel to the isothermal siirface. The 05servations of Wiedernann. Henneberg:. ant1 tlie author for the thertiial conductivity of mixtures, are worked out according to t h e three formulas and the results are aptly given 1)~-the author hen h e says "tliat t h e third formula is t h e least unsatisfactory." H . 7: n.
On colloidal solutions of metals. A7. Sfocki triiti L. I i r i i i u o . Zeif. phys. C/zeiu. 34,378 (1900) .-Reply to Zsigmoticly ( 4 , 547). 11". ZI,6.
