468 x Scientific Intelligence. 



conium frequently found in ordinary rocks. While this method 

 as described by Hillebrand was a satisfactory one for deter- 

 mining such quantities as from 0-02 to 0-2 per cent, there was 

 doubt about the composition of the washed and ignited precipi- 

 tate and, consequently, concerning the proper factor to be used 

 for larger quantities of the precipitate, as well as in regard to 

 other details of the determination. 



The present authors recommend the precipitation by means 

 of secondary ammonium phosphate added in excess to the extent 

 of 10 to 100 times the amount calculated from the ratio Zr: 

 P 2 5 , in a volume from 25 cc to 200 cc, according to the amount 

 of zirconium present, up to 0-1 g. The acidity of the solution 

 should be 20% sulphuric acid by weight. Hydrogen peroxide 

 should be added to prevent the precipitation of titanium, 10 cc 

 of this will do no harm. The temperature of precipitation 

 should be cold or preferably 40-50°, and the time of standing 

 before nitration should be two hours for larger amounts in 

 excess of 005 g. and 6 hours longer for smaller amounts. The 

 nitration should be made warm with decantation of the super- 

 natant liquid, and the washing should be done with 5% 

 ammonium nitrate solution in order to avoid hydrolysis and 

 consequent loss of phosphoric acid. The precipitate should be 

 ignited very carefully in a partly covered platinum crucible 

 until filter paper carbon is destroyed, followed by blasting or 

 its equivalent. The ignited precipitate has the composition 

 ZrP 2 7 , requiring the factor -4632 for Zr0 2 . This method 

 separates zirconium satisfactorily from iron, aluminium, chro- 

 mium, cerium and thorium, and in the presence of hydrogen 

 peroxide from titanium. — Jour. Amer. Chem. Soc, 41, 1801. 



h. l. w. 



2. An Introductory Course in Quantitative Chemical Analy- 

 sis; by George McPhail Smith. 8vo, pp. 206. New York, 

 1919 (The Macmillan Company). — This book is a rather elabo- 

 rate one for a laboratory manual, displaying many excellent 

 features. The introductory part, besides describing the opera- 

 tions, present a considerable amount of appropriate theoretical 

 matter in the line of physical chemistry. Practical courses in 

 gravimetric and volumetric analysis are presented with very 

 full and clear descriptions of the methods of procedure together 

 with numerous instructive notes in connection with each exer- 

 cise. A section of the book is devoted to stoichiometrical prob- 

 lems. A few examples of these are explained, and then 100 

 very instructive problems, without answers, are given. An 

 extensive series of questions concerning the practical exercises 

 is presented in another section. There are notes on the prepa- 

 ration of reagents, a list of apparatus for the student's desk, 

 and tables of four-place logarithms and antilogarithms. There 

 is also a table of atomic weights, but no gravimetric or volu- 

 metric factors are given. 



