Chemistry and Physics. 155 



6. Compounds of Hydrogen Peroxide toith Salts. — S. Tanatar 

 has prepared a carious molecular compound of hydrogen peroxide 

 and potassium fluoride with the composition corresponding to the 

 formula KFH 2 2 . It forms large monoclinic crystals and is pre- 

 pared by treating a very concentrated solution of the two sub-, 

 stances — hydrogen peroxide being in excess— with alcohol, then 

 separating the lower of two layers of liquid which form, treating 

 again with alcohol, and evaporating in a desiccator. In a some- 

 what similar manner the compound Na 2 S0 4 '9H 2 OH 2 2 was pre- 

 pared. This is evidently Glauber's salt in which one molecule of 

 water of crystallization is replaced by hydrogen peroxide. From 

 an alkaline solution of sodium nitrate the remarkable compound 

 NaN0 3 -Na 2 2 -8H 2 was produced. — Zeitschr. anorgan. Chem., 

 xxviii, 255. h. l. w. 



7. Drift of the Ether. — Dr. W. M. Hicks communicates a long 

 mathematical paper on Micbelson and Morley's experiment in 

 regard to the motion of the ether. He points out that reflection 

 produces a change in the wave-length of the reflected light. 

 Further, when the source of light moves with the apparatus, the 

 light incident at any instant on a plate does not come from the 

 position occupied by the source at that instant, but from a point 

 which it occupied at some interval before : consequently the 

 angle of incidence alters by a small quantity of the first order as 

 the direction of drift of the apparatus changes. The principal 

 result of the correction is that in the experiment of Michelson 

 and Morley the effect to be expected is the reverse of that 

 hitherto supposed. — Phil. Mag., Jan. 1902, pp. 9-42. J. t. 



8. The Clearing of troubled Solutions. — G-. Quincke reviews 

 the work of previous writers on the causes of the suspension of 

 fine particles of various substances in water. Prof. J. J. Thomson 

 and Mr. Hardy sought the ground of this long suspension in the 

 electromotive force at the boundary of the suspended particles 

 and the surrounding liquid, which opposed the movement of the 

 solid particles. Since according to Dorn electric work would be 

 afforded by a displacement of the particles, the working would 

 be the same as if the viscosity of the fluid should be increased. 

 Quincke's observations do not support this hypothesis. He finds 

 the main cause of the suspension in the hydrodynamic forces, 

 which the swimming or slowly falling particles excite in the sur- 

 rounding fluid. Quincke does not agree with Barus, Hardy and 

 Spring, that a phenomenon of electrolysis enters. He sums up 

 his observations under ten heads, which relate to the various 

 phenomena observed in solutions containing suspended particles. 

 — Ann. der Physik, No. 1, 1902, pp. 57-96. J. t. 



9. Displacement Currents. — In a previous paper, M. R. Blond- 

 lot showed that if a mass of air is moved in a magnetic field 

 normally to the lines of force, no electric displacement results in 

 this mass of air. From this it follows that a mass of air which 

 is the seat of an electric displacement should undergo no action 

 in a magnetic field. If the principle of action and reaction is 



