Notices respecting New Books. 65 



contrast of facts to hold my judgement as yet in suspense. It 

 is, indeed, to me an annoying matter to find how many sub- 

 jects there are in electrical science, on which, if I were asked 

 for an opinion, I should have to say, I cannot tell, I do not 

 know; but, on the other hand, it is encouraging to think that 

 these are they which if pursued industriously, experimentally, 

 and thoughtfully, will lead to new discoveries. Such a sub- 

 ject, for instance, occurs in the currents produced by dynamic 

 induction, which you say it will be admitted do not require for 

 their production intervening ponderable atoms. For my own 

 part, I more than half incline to think they do require these 

 intervening particles, that is, where any particles intervene 

 (1729. 1733. 1738.). But on this question, as on many others, 

 I have not yet made up my mind. Allow me, therefore, here 

 to conclude my letter; and believe me to be, with the highest 

 esteem, My dear Sir, 



Your obliged and faithful Servant, 

 Royal Institution, April 18, 1840. M. FARADAY. 



X. Notices respecting New Books. 



Report on the Progress of Vegetable Physiology during the Year 1837. 

 By F. J. F. MEYEN, M.D., Professor of Botany in the University 

 of Berlin. Translated from the German, by WILLIAM FRANCIS, 

 A.L.S. London, 1839. 8vo, pp. 158. 



OUR readers will doubtless remember the valuable Report on the 

 Progress of Vegetable Physiology for the year 1836, which 

 appeared in our pages about two years since*. The high position 

 occupied by Professor Meyen in this department of science, and the 

 vast increase which is constantly being made in the amount of our 

 knowledge of it, by the labours of the industrious physiologists of 

 Germany, combine to give these reports a peculiar value. A great 

 part of the information contained in them would not have found its 

 way to this country in any other shape ; and it is much more 

 agreeable to obtain it in the condensed form it assumes after being 

 submitted to the Professor's compressorium, which squeezes away 

 the lighter fluid with which it is diluted, and retains the solid 

 matter, than in its original state. The Report at present before us 

 is equally full of valuable information with the former one ; and, 

 when its much greater extent is considered, its importance as a 

 contribution to scientific literature will be apparent. The rapid 

 advance of discovery in this most interesting science will give, we 

 are assured, a progressively increasing value to these reports : and 

 when the utility of a well-executed translation is considered, espe- 

 cially from a language which needs long study and familiarity to 

 give a certainty of the author's meaning being understood, we 



* Lond. and Edinb. Phil. Mag., vol. ix. p. 381, et seq. 

 Phil. Mag. S.3. Vol. 17. No. 107. July 1840. F 



