Chemistry and Physics. 471 



acetic acid, potassium iodide is added, and the resulting free 

 iodine is titrated with sodium thiosulphate solution. The ferric 

 salt is determined by taking another portion of the original 

 solution, making it acid with acetic acid only, adding potassium 

 iodide and titrating as before. The difference gives the amount 

 of iron. Aluminium and zinc do not interfere, so that the 

 method has a wide application. — Chein. Zeitung, 41, 763 

 (through Jour. Chem. Soc). h. l. w. 



3. Chemistry in the Home, by Henry T. Weed. 12mo, pp. 

 385. New York, 1915-16 (American Book Company). — This 

 text-book, which is intended for use in high schools, is accom- 

 panied by a loose-leaf laboratory manual containing directions 

 for experiments with forms for reporting the results. 



The course of study presented by this book is a rather exten- 

 sive one for its grade, and it aims to train the pupils in scien- 

 tific thinking and to give them a fund of information concern- 

 ing the chemistry of everyday things related to industries and 

 the home. Although the fundamental chemical theories are 

 clearly presented, this side of the subject is not treated as fully 

 as is often the case with high school text-books. On the other 

 hand, the practical applications of chemistry that are of every- 

 day importance are treated with unusual fullness, and it appears 

 that these topics should be of much interest and value to the 

 pupils. The subject of foods receives particularly extensive 

 treatment, including elaborate tables of the compositions and 

 calories produced by many articles of diet, tables of daily rations 

 and diagrams of the costs of food constituents in various 

 materials. 



The book and the laboratory manual are well illustrated, and 

 they give the impression that they present an unusually inter- 

 esting and practical course of chemical study. The author states 

 that constant effort has been made to keep the language and style 

 simple, and in this he seems to have been generally successful, 

 but here and there the simple explanations appear to be some- 

 what unsatisfactory. For example, after mentioning the lumi- 

 niferous ether as an extremely rarified substance with which we 

 believe all space to be filled, stating that it is a totally different 

 substance from the liquid used by surgeons, and indicating that 

 it is impossible to pump more ether into a vessel, or out of it. 

 than it already contains, because it would leak through the sides 

 of the vessel, he says, "If we could magnify a drop of water 

 sufficiently, it would, somewhat resemble lemon jelly, filled, not 

 too closely, with caraway seeds. The lemon jelly would repre- 

 sent the ether, and the caraway seeds the particles (molecules) 

 of water." He then goes on to show the similarity of wave- 

 motion in the luminiferous ether to the well-known quiver of 

 lemon jelly on the table. h. l. w. 



4. Chemistry, First Stage; by F. P. Armitage. 16mo, pp. 

 80. London, 1918 (Longmans, Green and Co.). — This very 



