Chemistry and Physics. 83 



caused the liquid to boil violently. It appears to the reviewer 

 that this explanation overlooks the chief cause of the sudden 

 boiling, namely, the great amount of heat that is set free by the 

 sudden crystallization of a large amount of salt from a supersatu- 

 rated solution. This sudden warming under low pressure and the 

 presence of much solid salt in the liquid explain satisfactorily 

 these interesting accidents. — Chem. JVews, xcviii, 27. h. l. w. 



3. Constituents of Ytterbium. — Aiter von Welsbach, whose 

 work on the rare earths is well known, particularly his splitting 

 up of old didymium into neodymium and praseodymium, has suc- 

 ceeded in obtaining two earths from ytterbium. This was done 

 by long continued fractionation, particularly of the ammonium 

 double oxalates. He has named the new elements, Aldebaranium 

 and Cassiopeium, Ad and Cp. Their distinguishing feature is 

 in their spark spectra. Their reactions are those of ytterbium, 

 and they cannot be distinguished from one another by any 

 chemical reactions. They form only one oxide, the sesquioxide, 

 which is stable at a red heat. All the salts are colorless if the 

 acid is not colored. The atomic weights found were 172*90 for 

 Ad and 74-23 for Cp. The cassiopeium was not obtained abso- 

 lutely free from the other earth, but it is the author's intention 

 to repeat the separation with a larger amount of material in order 

 to obtain purer cassiopeium, which he designates as the last in the 

 series of rare earths. It will take six or eight years to complete 

 this tedious task.— 3Ionatshefle, xxix, 2. H. l. w. 



4. A New Form of u Tin Infection." — It has been known for 

 a long time that metallic tin at low temperatures is subject to a 

 physical change which renders it grey and very friable. For 

 instance, it is said that the tin buttons on the uniforms of 

 Napoleon's soldiers in the Russian campaign fell to pieces. This 

 behavior was formerly attributed to the simple action of low tem- 

 perature, but in recent times it has been shown that it is due to a 

 recrystallization which can be communicated to any piece of tin 

 at a low temperature, by contact with an affected piece of tin, or, 

 as it may be termed, by inoculation. It has been recently observed 

 by von HAssLiNGERthat a piece of tinware soldered with tin which 

 had been stored for two years in a place which was alwaj^s heated 

 in winter showed a dull surface, a crystalline structure under the 

 microscope, and a friability corresponding to the change that 

 usually takes place only at low temperatures. It was found 

 further that this material was capable of inoculating unchanged 

 tin, either in the form of ordinary tin plate, tin foil or cast tin, at 

 such temperatures as 7°, 19° and 37° C. The growth of the 

 infected spots of nearly circular form was at the ra>e of from 3 

 to 5 mm per day, but it was noticeable that this growth became 

 slow as it extended farther from the inoculated center. — Monat- 

 shefte, xxix, 787. h. l. w. 



5. The Heat Evolved by Radium. — A new determination of 

 this constant has been made by von Schweidler and Hess, with 

 the result that 118*0 gram-calories per hour were found. Previ- 



