432 Scientific Intelligence. 



with a known amount of a cobalt compound by following tbe 

 described analytical process. — Jour. Indus, and Eng. Chem., 

 viii, 901. ii. l. ay. 



3. The Determination of Aluminium as Oxide. — William 

 Blum of the U. S. Bureau of Standards has made an extensive 

 study of this commonly used method. The novel feature of the 

 procedure recommended consists in adding a few drops of an 

 alcoholic solution of methyl red (0-2 per cent), heating just to 

 boiling, and adding ammonia drop by drop until the color changes 

 to a distinct yellow, then boiling for one or two minutes and filter- 

 ing immediately. It is claimed that calcium and barium, if pres- 

 ent, do not form carbonates with the carbon dioxide of the air 

 under these conditions. Attention is called to the well known 

 advantage of the presence of ammonium chloride when the 

 precipitation is made, and washing with a 2 per cent solution of 

 ammonium chloride is recommended. Ignition of the oxide in a 

 platinum crucible over the blast lamp for about five minutes is 

 advised. Attention is called to the importance of keeping the 

 crucible closely covered while cooling and weighing, and the 

 importance of weighing very rapidly, but the suspicion arises that 

 at the Bureau of Standards they have been following the bad 

 practice of trying to weigh warm crucibles ; for the following 

 suggestive statement is made : " Tests at this Bureau have shown 

 that in common with most substances capable of absorbing mois- 

 ture (even those not intrinsically hygroscopic) recently ignited 

 A1 2 3 absorbs within the first ten minutes' exposure to the atmos- 

 phere a large proportion of the water which it will absorb in 

 twenty-four hours." It is well known to experienced chemists 

 that a slightly warm crucible, when placed upon the balance pan, 

 shows a deficiency in weight on account of the ascending current 

 of air produced, and that it then requires something like ten min- 

 utes for the crucible to cool sufficiently to show its true weight. 

 It is advisable either to supply the desiccator with a thermometer, 

 or to touch the face with the crucible before weighing, to make 

 sure that it is cold. — Jour. Arner.. Chem. Soc., xxxviii, 1282. 



H. L. W. 



4. Ozone, Its Manufacture, Properties, and Uses ; by A. Vos- 

 maer, 8vo, pp. 197. New York, 1916 (D. Van Nostrand Com- 

 pany). — Part I of this book, comprising only 18 pages, deals with 

 the early history, constitution, nature, occurrence, and properties 

 of ozone, and the te6tsforit. The second part presents an exten- 

 sive discussion of the manufacture of the substance, while the 

 third part is devoted to its uses, and the last part gives a list of 

 the United States patents, and an extensive bibliography. There 

 are *75 illustrations and diagrams. The author has had a long 

 period of experience with ozone in Holland, and is thus able to 

 give much interesting information. Some of the apparatus and 

 methods described are of his own invention, but it appears that 

 he gives proper credit to other methods than his own, and that 

 he has endeavored to treat the subject from a scientific stand- 



