Notices respecting New Boohs. 393 



ments were carried out again to test the suggestion, with 

 water, with dilute, and with concentrated solutions. The result 

 was, as I convinced myself and others, that not a trace of ice 

 ever froze to the bulb of the thermometer under any condition. 



When the thermometer was quickly removed from the 

 water, a few snow-like flakes came up with it. These were 

 in no sense attached to the bulb, but floated off at once with 

 the liquid wdrich had adhered to it. It must then be stated 

 emphatically that this assumption of Wildermann, as far as 

 the work with my thermometer is concerned, receives abso- 

 lutely no support from the experimental facts'*. 

 Chemical Laboratory, 



Johns Hopkins Univ., June 1895. 



XXXII. Notices respecting New Boohs. 



An Introduction to Chemical Crystallography . By Andkeas Pock:, 

 Ph.D., translated and edited by William J. Pope, with a preface 

 by N. Stoby-M askelyne, M.A., F.B.8. Pp. 189 & xvi. 8vo. 

 (Oxford: Clarendon Press. 1895.) 



HPHE importance of a knowledge of crystallography to all workers 

 -*- in the fields of chemical research has not hitherto been sufficiently 

 recognized either at home or abroad. It is therefore an encouraging 

 sign of the times that this little book has been prepared for the 

 use of students in the Central Technical College, and also in 

 order to call the attention of chemists to the important relations 

 which exist between crystalline form and chemical composition. 

 Mr. Pope deserves accordingly the gratitude of all who are inter- 

 ested in the progress of chemistry in this country for his excellent 

 translation of Dr. Pock's Einleitung in die chemische Krystallographie. 



The book is divided into twenty-five short chapters : the first 

 fifteen of these deal with the nature of crystals, solutions, and 

 double salts, the growth of crystals and their production in the 

 laboratory. 



The consideration of the relations between chemical composition 

 and crystalline form begins on page 84: with an historical sketch 

 of isomorphism, and in the chapters which follow the properties of 



* In a recent publication (Phil. Mag. xl. p. 120, 1895) Wildermann 

 has quoted Ostwald as saying that my freezing-point method required 

 further development (in "Wildermann's hands), u because the results ob- 

 tained for non-electrolytes by this method do not agree with the funda- 

 mental generalizations of the modern Theory of Solutions." 



It is difficult for a student of the great Thinker to conceive of him 

 judging results by any theory, thus taking a position which accords 

 priority to the theory, rather than to the experimental data on which it 

 is founded, and by which it must be tested. 



It also appears to me that it would have been more in accord with 

 scientific custom had Dr. Wildermann granted Ostwald the opportunity 

 of offering his own criticism, which, had it ever appeared first-hand, 

 would have differed from the second-hand version in this, that it would 

 have been accompanied by the legitimate reasons on which it was based. 



Phil. Mag. S. 5. Vol. 40. No. 245. Oct. 1895. 2 E 



