Notices respecting New Boohs. 73 



The net result of this paper is that Haecker's (and Ber- 

 noulli's) formula is merely another way of saying that the 

 lifting-power of magnets in which the intensity of the mag- 

 netic induction has heen carried up to an equal degree, is 

 proportional to the polar surface. And Haecker's coefficient 

 is proportional to B 2 through that surface. 



X. Notices respecting New Books. 



Watts's Dictionary of Chemistry, revised and entirely rewritten 

 By H. Fosteb Morlet, 31. A., D.Sc, and M. M. Pattisox 

 Mule. 31. A., assisted by eminent Contributors. In Four Volumes. 

 Tol. I. Longmans, Green, & Co., 1SSS. 



HPHE standard work of reference in the English language used by 

 -*- chemists in this country and America is the well known 

 ' Dictionary of Chemistry and the allied branches of other Sciences ' 

 bearing the name of the late Mr. Henry Watts as author. But 

 this work was commenced more than a quarter of a century ago, 

 and was only completed in 1881. During that period the rapid 

 advancement of chemical science made it necessary to issue four 

 supplementary volumes containing altogether between four and 

 five thousand pages of additional matter. So rapid is the growth 

 of the science, however, owing to the continuous increase in the 

 number of workers, that an interval of seven years is sufficient to 

 make even the last u Supplement " require further supplementing ; 

 and the late Mr. Watte had undertaken to revise the whole work 

 and bring out a new and more condensed edition, representing the 

 present state of chemical science, when his labours were cut short 

 by drath. The lamented author had only gone so far as to pre- 

 pare a code of "Instructions" for the use of contributors, and had 

 written some sixty odd pages of the new edition at the time of his 

 decease. The completion of the work has been entrusted to Dr. 

 H. Foster Morley and Mr. Fattison Muir, who have utilized Mr. 

 "Watts's materials as far as they go, but who have of course been 

 obliged to supply the greater part of the matter which fills the 

 pages of the present work. 



The chief difference in form between the old edition and the 

 new one, of which the first volume is before us, is the greater 

 condensation which the publishers have insisted upon in the present 

 issue. Instead of the nine thick volumes which chemists have been 

 so long in the habit of consulting, the new edition is to be com- 

 pressed into four volumes of about 75<» pages each. Whether this 

 condensation can be effected without serious injury to the Dic- 

 tionary will depend entirely upon the skill and judgment which 

 the compilers exercise in carrying on the work : it must be confessed 

 that a^ far as the present volume is concerned there is no complaint 

 to be made on this score. The 752 pages of the first volume are 

 as replete with well organized information as could be desired by 

 the most rapid of readers. There can be no doubt that much of 



