Chemistry and Physics. 459 



combines with atmospheric oxygen with great readiness, forming 

 di-triphenylmethylperoxide (C 6 H 6 ) 3 C.0 2 .C(C 6 H 5 ) 3 . This property 

 renders the preparation of the unsaturated hydrocarbon in the 

 pure state extremely difficult, and although the author has suc- 

 ceeded in obtaining large crystals of it, he has not yet been able 

 to wash them without the formation of the peroxide. If subse- 

 quent investigation confirms the preliminary conclusions, the com- 

 pound will possess great theoretical interest as being the first 

 unsaturated compound of the kind, and furnishing the first definite 

 evidence of the existence of the trivalent carbon atom. — Jour. 

 Am. Chetn. Soc, xxii, 757. h. l. w. 



3. On the Phosphorescence of Inorganic Chemical Prepara- 

 tions. — This subject has been studied by E. Goldstein. The 

 method of investigation consisted in placing the substance under 

 examination in a properly shaped tube and waving the latter 

 back and forth in a cone of cathode rays. The nature of the 

 phosphorescence could be determined from the length of the 

 observed trail of light. The examination of various pure samples 

 of a substance showed that the color of light attributed to it by 

 previous investigators becomes weaker as the substance becomes 

 purer. On the contrary, the light which appears at the point of 

 contact with the cathode rays, and which lasts only during the 

 illumination, becomes continually brighter as the purity increases. 

 The substances investigated may be divided into two groups in 

 respect to their phosphorescent light. In the case of the sul- 

 phates, carbonates, phosphates, borates, silicates, chlorides, brom- 

 ides, fluorides, oxides, and hydroxides of Li, Na, K, Rb, Cs, Ca, 

 Sr, Ba, Al, Zr, Mg, Be, Zn, and Cd the color is blue, violet-blue, 

 or in a few instances violet. Salts of Cu, Cr. Mn, IT, NL Co, Pb, 

 Ce, La, Y, Er, Pr, and Ne belong to the other group. The latter, 

 when admixed in very small amounts with compounds of the first 

 group, give a light which in most cases exceeds the blue light in 

 intensity and duration, but corresponding phenomena could not 

 be observed when reciprocal additions from the first group were 

 made. There is a maximum in the strength of the colored light, 

 for it decreases again when the small amount of substance from 

 group 2 is increased beyond a certain limit. The presence of 

 moisture may possibly be assigned as the reason for the similar 

 luminosity of the substances of the first group. The effect of 

 additions from the second group may possibly be due to greater 

 power of absorption or else to the occurrence of decomposition. — 

 Chem. Central- Blatt, 1900, ii, 756. h. l. w. 



4. Weight of Hydrogen Desiccated by Liquid Air. — Lord 

 Rayleigh has found that the density of hydrogen dried by cool- 

 ing with liquid air is the same as that obtained when the gas is 

 dried with phosphorus pentoxide. This was to be expected, for 

 it was shown by Morley in an article published in this Journal in 

 September, 1887, that this oxide is a practically perfect dryer for 

 gases, but it is satisfactory to have a confirmation of this 

 important fact. — Proc. Roy. Soc., lxvi, 334. ' h. l. w. 



