220 Amlyses of Books* " [Sept. 



they are attacked much earlier ht/ the rot ; and that the sap rises 

 to the top of the tree at full moouy and falls in proportion to the 

 moon's decrease ; and this effect is common to ail species of trees 

 with which this gentleman was acquainted. 



It will be perceived that these observations are confined to 

 the continent of South America and islands adjoining; but if 

 the moon has a correspondent inttuence in other countries, 

 (which there is no reason to doubt) and this gentleman's ob- 

 servations be correct, the practical importance of them in 

 felling timber deserves the utmost thanks from those persons 

 who are in any way interested in practices of this kind, as well 

 as from society at large. 



Article IX. 

 Analyses of Books. 



^Philosophical Transactions of the Royal Society of London, for 

 182'4. Part 11. 



{Concluded from p. 65.) 



XVI. A Comparison of Barometrical Measurement with the 

 Trigonometrical Determination of a Height at Spitzhergen. By 

 Capt. E. Sabine, FRS. 



An account of the results of this comparison will be found in 

 the Annals for May, 1824, p. 385. 



XVII. Experimental Inquiries relative to the Distrihutioji and 

 Changes of the Magnetic Intensity in Ships of War. By George 

 Harvey, Lsq. : communicated by John Barrow, Esq. FRS. 



We should not be able to give our readers an adequate idea 

 of the results of these inquiries, occupying above forty pages of 

 the Transactions, in the confined space we could devote to the 

 subject, and must, therefore, refer them to the paper itself. 

 This we must also do, and tor the same reason, with respect to 

 another valuable paper by Mr. Harvey, mentioned below, but of 

 which a short notice has already appeared in the Annals. 



XVIII. Experiments on the Ela6ticitij and Strength of Hard 

 and Soft Steel. In a Letter to Thomas Young, MD. For. Sec. 

 RS. By Mr. Thomas Tredgold, Civil Engineer. 



" If a piece of very hard steel be softened," Mr. Tredgold 

 states, addressing Dr. Young, " it is natural to suppose that the 

 operation will produce a corresponding change in the elastic 

 power, and that the same load would produce a greater flexure 

 m the soft state than in the hard one, when all other circum- 

 stances were the same. Mr. Coulomb inferred from some com- 

 parative expeiiments on small specimens, that the state of 



