Tredgold's Elementaiy Principles of Carpentry. 49 



is to be found in our language: we were glad to find here, in 

 opposition to certain wild schemes which have been set afloat, 

 that the extent of the span of wooden Bridges, is perfectly li- 

 mited bv the nature of the Material. 



The ninth Section treats on Jo'nils, Scarfing and Straps ; on 

 which many important and practical maxims and methods of con- 

 struction are net down and shown. 



The tenth Section contains matter, which we anxiously hope 

 that the Author may find encouragement to enlarge upon, in a 

 future Edition, or else in a separate Work: it is, on the Nature 

 and Properties of the Timber furnished by different species of 

 Trees, and here occupies 80 pages, of truly valuable details, on 

 the nature of Timber, with reference to the Ages of the Trees, 

 and the periods of the year in which they are felled : on the 

 methods of Seasoning, the causes of Decay, and methods for its 

 prevention: the whole preceded, by a simple yet scientific classi- 

 fication of the different kinds of Wood, as exhibited in their 

 grain or structure, followed by a description of 22 useful kinds of 

 Wood. 



The Laws of Seasoning or drying, are here laid down, showing 

 the rates at which pieces of different sizes become dry, and en- 

 forcing the advantages derivable, from reducing Timber into the 

 smallest Scantling that its uses will admit, so soon as the Tree 

 or its larger divisions, have become sufficiently seasoneti to pre- 

 vent splitting. 



Several Tables of the weight of a cubic foot of Timber, in dif- 

 ferent stages of drying, are collected : but as the shrinkage has 

 been omitted to be observed and recorded, in all of these except 

 the first in p. IGO, our Author has not been able to deduce from 

 these Tables, any satisfactory mean loss of weight ; — we find the 

 mean of all the experiments on different Woods mentioned in 

 these Tables, to give 24-4 per cent, as tlie loss in drying, or very 

 near \ of the whole weight ; but for the above and other reasons 

 drawn from experience, the average degree of loss of weight 

 which has been sustained, by Woods fit for the Joiner's uses, is 

 in p. 163 stated by our Author, at ^ of the whole weight. Re- 

 sinous Woods may be presumed to lose less than others, and pro- 

 bably, each kind of Wood may approximate to some particular 

 degree of loss ; the whole subject requires a closer experimental 

 investigation, and this we hope that the Author may be enabled 

 to supply, in a future Edition. 



Two species of English Oak arc ppint^d out by our Author, 

 and one of them shown to possess very valuable properties, com- 

 pared with the other : Gentlemen intending to plant for future 

 Timber, or those concerned in Naval Arcliilecturr, cannot too 

 Vol. .OG. No. 2(>7. Juhj 1S2(). fi 'oon 



