310 Notices respecting New Books. 



bridges with about twenty pages of good practical observations 

 on forcing the passage of rivers. 



The fifth section contains the method of making bridges on 

 rafts of timber, on casks, on air-tight cases, and on inflated skins. ' 

 The different cliapters are interspersed with a variety of theorems 

 and details, of considerable use in practice. 



The sixth section describes the construction of carriage-bridges 

 and rope-bridges. In this is given Colonel Sturgeon's celebrated 

 rope-bridge across the broken arch of the bridge of Alcantara, 

 which appears to have been a very complete one. 



The last or seventh section contains the construction of bridges 

 on trestles; on piles; on trusses, and other principles of carpen- 

 try. Among the latter, is an account of a wooden arch of 250 

 feet span, across Portsmouth-river in North America, which may 

 serve as a good pattern, when the beams that can be obtained in 

 the country are short, or when portable pieces of no great length 

 are carried with the armv. It appears rather too complicated for 

 hasty military purposes; but may be advantageously applied as a 

 permanent bridge over a river of no great width. Its construc- 

 tion affords good hints to builders in general. The chapter con- 

 cludes with practical modes of passing small rivers by felling trees 

 across them in such directions, that they may combine with each 

 other in forming a communication. 



A tolerably copious index is subjoined ; and the plates, which 

 are thirteen in number, are well engraved, and illustrative. 



To an experienced engineer, many other expedients and methods 

 will occur,besides those which he meets with on perusing this little 

 work; but, probably, the author thought with good reason, that 

 they would have increased the size beyond portability, and the ex- 

 pense beyond the reach of general purchasers. The plan and ex- 

 ecution of the book is however good, and may be easily improved 

 and extended, if the public should require other editions, of which 

 there is little doubt when it becomes sufficiently known. 



Chemical Amusement, comprising a Series of curious and in- 

 structive Experiments in Chemistry , which are easily per- 

 formed and unattended by Danger; the third Edition with 

 Plates, and considerably enlarged. By Fredrick Accum, 

 Operative Chemist, Lecturer on Practical Chemistry, on 

 Mineralogy, M.R.LA. F.L.S. M.A.S. R.S.J. Berlin, ^c. 

 This work, of which a third edition has appeared, has been 

 written with a view to blend chemical science with rational 

 amusement. To the student it may serve as a very useful manual 

 for performing a variety of curious and instructive experiments, 

 well calculated for illustrating at a cheap rate, and in a pleasing 

 wanner, the most striking facts the science of chemistry has to 



offer. 



