398 Scientific Intelligence. 



the .passage of air through the walls of an exhausted vessel. He 

 found that a perfectly transparent bulb of quartz glass when kept 

 at 1300° for twenty hours in an electric resistance furnace became 

 white and translucent like frosted glass, and with several 

 exhausted bulbs treated similarly he found a very considerable 

 leakage of air. The leakage was found to occur not only Avhile 

 a bulb was heated but also at ordinary temperature after devitri- 

 fication had taken place. A micro-photograph of a devitrified 

 silica bulb showed a surface cracked all over into the appearance 

 of cells, and many of the cells showed a decided hexagonal out- 

 line. Crookes has observed a similar appearance when a silica 

 dish, originally clear and transparent, was used for evaporating 

 the solution of 100 msr of pure radium bromide. Patches appeai-ed 

 on the bottom having a dull, roughened appearance, and upon 

 microscopic examination they showed a structure very similar to 

 that of the devitrified bulb. He concludes that radium at the 

 temperature of boiling water can de vitrify quartz glass, but he 

 has not seen this effect upon the surface of glass or silica bottles 

 in which radium salts have been kept in the cold for several years. 

 — Chem. JVews, cv, 205. h. l. w. 



3. The Presence of Formaldehyde in Plants. — According to 

 Baeyer's assimilation hypothesis, the plant first reduces carbonic 

 acid to formaldehyde, and then condenses this to carbohydrates. 

 In order to establish this hypothesis it is of great importance to 

 detect the presence of formaldehyde in plants. Cuetius and 

 Franzen show that all the tests that have been previously used 

 for this purpose have been unreliable on account of the interfer- 

 ence of other aldehydes, and they conclude that formaldehyde in 

 plants has not been detected heretofore. Therefore, these 

 chemists have made a new investigation of the subject, and it 

 appears that they have definitely established the presence of 

 formaldehyde in the leaves of a certain plant, and have thus 

 established the basis of Baeyer's theory. They used the leaves of 

 a certain kind of beech, "Hainbuchenblatter," in large quantity. 

 As much as \\ tons of the leaves, altogether, were put through 

 the process, which was an elaborate one consisting of several dis- 

 tillations, the conversion of the aldehydes into the corresponding 

 acids by means of silver oxide, and after further separations the 

 final detection by several methods of the resulting formic acid. 

 Quantitative determinations showed that l kg of the leaves con- 

 tained only 0-00086 g of formaldehyde, or less than one part per 

 million. — Perichte, xlv, 1715. h. l. w. 



4. The Determination of Sulphur in Insoluble Sutyhides. — T. 

 St. Warunis, having previously worked out a method for the 

 determination of sulphur in coals, has applied the same principle 

 successfully to the analysis of sulphides. A portion of , 5 S of 

 the sulphide, ground exceedingly fine, is intimately mixed in a 

 spacious porcelain crucible with a mixture of 4 parts of dry 

 sodium carbonate and 3 parts of copper oxide, the whole is cov- 

 ered with a thin layer of the same mixture and is heated gently 



