68 Scientific Intelligence. 



dilute solutions of cane sugar containing 0*683 parts in 100 parts 

 of water the reduction of the freezing point is 0*042 and the 

 molecular depression is 20*9; calling the molecular mass of the 

 sugar 342. If the solution contains 2*848 parts of sugar, the 

 freezing point is lowered 0*168 and the molecular depression is 

 20*1. For 7*297 parts in 100, the lowering of the freezing point 

 is 0*422 and the molecular depression 19*S. For a solution of 

 39*040 parts, the freezing point is lowered 2*474 and the molecular 

 depression is 21*6. Plotting the lowering of the freezing point 

 as the abscissa and the molecular depression as the ordinate, a 

 curve is obtained coinciding substantially, except at the origin, 

 with one given by the author in 1886 and criticised by Arrhenius, 

 as to the portion relating to very dilute solutions ; thus confirming 

 the original statement of the author, that when the dilution ex- 

 ceeds certain limits, the molecular depression of cane sugar, like 

 that of other substances, suffers an increase. This increase is so 

 small, however, that it appears to confirm the opinion of the 

 Swedish chemist. These results show the advantages of the new 

 method. — G. H., cxiv, 114; Zeitschr. physikal. Chem., ix, 343, 

 April, 1892. G. f. b. 



5. Chemical Lecture Experiments. Non-metallic Elements, 

 by G. S. Newth. 323 pp., 8vo. London, 1892 (Longmans, Green 

 & Co.). — The chemical lecturer will find a valuable companion in 

 this volume, for it desci'ibes for him, clearly and with sufficient 

 detail as to manipulation, such experiments as he is likely to need 

 to present to his audience. For the student it is also of hardly 

 less value, since it can be used by him in connection with the lec- 

 tures which he is attending as supplementary and explanatory to 

 them. The experiments are well chosen and cover the important 

 properties of the non-metallic elements, including also some related 

 physical phenomena, as the liquefaction of gases. The closing 

 chapter is devoted to lantern illustrations, and an appendix gives 

 a series of useful tables of chemical data. 



6. Color Photography. — M. G. Lippman states that albumen- 

 ized and gelatinized plates soaked in bichromate of potash may 

 be employed for photographing in colors. They are used like 

 silver salt plates. The colors appear after immersion in water 

 which develops and fixes the image. The latter disappears on 

 drying, but reappears when the plate is soaked. The colors are 

 very brilliant, and are produced by the interference of hygro- 

 scopic and non-hygroscopic layers with variable refractive 

 indices. — Comptes Rendus, Oct. 24, 1892. J. t. 



7. Infra red spectra of the Alkali Metals. — Mr. Benjamin 

 W. Snow in studying this subject has employed the bolometer 

 with a very delicate galvanometer. The needle of the latter was 

 suspended by a quartz fiber 40 cm long. With a scale distance of 

 3 m a deflection of l mm corresponded to a current of 1*5X10~ " 

 amperes. A silicate-flint prism was employed to avoid the over- 

 lapping of diffraction-grating spectra. An arc light was used 

 and a hole having,' been bored through the center of the carbon a 



