222 Scientific Intelligence. 



less completely split up into their constituents or ions." The 

 substances detectible by reagents therefore are these free ions 

 only. Thus the chlorine in metallic chlorides is an ion when in 

 solution and hence reacts with silver nitrate; while chlorates, 

 chlor-acetates and chloroform do not so react, since these sub- 

 stances contain no chlorine ions. The ions of potassium chlorate 

 are K and C10 3 and it is these ions which react with suitable 

 reagents. In short all the reactions of analytical chemistry when 

 they occur in solution are ionic reactions. Thus the author de- 

 fines an acid to be a compound which contains hydrogen as an 

 ion when in aqueous solution and a base to be one which under 

 like circumstances contains the ion hydroxy!. The reading of 

 such a book as this by the student cannot fail to be of the great- 

 est advantage to him, since it leads him to consider the philosophy 

 underlying his analytical processes and thus broadens out his 

 horizon. The book is worthily dedicated to Wislicenus. g. f. b. 



7. Lehrbuch der Allgemeinen C hemic ; von Dr. Wilh. Ost- 

 wald, Professor an der Universitat zu Leipzig. In zwei Banden. 

 Zweiten Bandes, zweiter Teil. Venoandtschaftslehre. Zweite 

 Lieferung,Bogen 14-26. Zweite umgearbeitete Auflage. Leipzig, 

 1897 (W. Engelmann). — This is the part last issued of the 

 remarkable Treatise on General Chemistry by Ostwald, now ap- 

 pearing in its second edition. It is not too much to say that it 

 appears destined to exert upon the science of chemistry a more 

 important influence than any other similar treatise now extant. 



G. F. B. 



8. Inorganic Chemical Preparations ; by Frank H. Thoep, 

 Ph.D., Instructor in Industrial Chemistry in the Mass. Inst, of 

 Technology. 8vo, pp. iv, 238, Boston, 1896 (Ginn & Co.)— The 

 author has sought in this manual to provide the student with such 

 simple directions in manipulation and experimentation as shall 

 enable him to prepare the 100 substances mentioned in it with 

 accuracy and success. The matters it treats of are well consid- 

 ered and the book will no doubt serve a useful purpose in instruc- 

 tion. G. F. B. 



9. Experimental Physics; by William A. Stone, A.B., In- 

 structor in Physics at the Phillips Exeter Academy, 12mo, pp. vi, 

 378. Boston, 1897 (Ginn & Co.) — An elementary laboratory 

 manual for students in preparatory schools and academies. The 

 subjects seem well selected, the descriptions accurate, the direc- 

 tions plain, the illustrations good, and the questions upon the 

 work suggestive. g. f. b. 



10. Physical Experiments ; A Manual and Note Book. By 

 Alfred P. Gage, Ph.D., 8vo, pp. ix, 97, Boston, 1897 (Ginn & 

 Co.) — A laboratory note book containing, among other exercises, 

 those required for admission to Harvard University. g. f. b. 



11. Transmission of Radiant Heat by Gases at Varying Pres- 

 sures. — Charles L. Brush shows that Dulong and Petit's sixth 

 la w : " The cooling power of a fluid diminishes in a geometrical pro- 

 gression when its tension itself diminishes in a geometrical pro- 



