528 



SCIENCE. 



[N. S. Vol. XII. No. 301. 



upon the reader, while the other parts are 

 without interest to those to whom the argu- 

 ment might appeal. It is difficult to imagine 

 what class of readers the author intended to 

 serve. Like most books written from the Conti- 

 nental point of view — i. e. , starting out with es- 

 tablished conditions of forestry practice — much 

 is unpalatable and of little import to the Amer- 

 ican reader. The title, division and treatment 

 of the subject also are novel with the author, 

 and not always fortunate. The term ' ex- 

 ploitation ' does not, as in English, mean the 

 mere rough utilization, but the very opposite, 

 a regulated management. Under exploita- 

 tion technique he discusses not only the methods 

 of regulating the management of a forest for con- 

 tinuous revenue, but also silvi-cultural opera- 

 tions — i. e. , the methods of securing the wood- 

 crop — -while under exploitation commerciale the 

 methods of harvesting the crop are discussed, 

 and the commercial considerations that enter 

 into it either with or without reference to the 

 future conditions of the property. From this 

 little is to be learned for our practice. Yet it 

 is interesting to note that evidently good for- 

 estry practice is not as general among private 

 forest-owners in France as is usually supposed, 

 for the author declares silvi-culture ' a new 

 art,' primitive in its development, deficient in 

 scientific basis and 'official' — i. e., practiced 

 mainly by the government officials in govern- 

 ment forests. We agree with the author that 

 forestry as a business commends itself mainly 

 to rich people, to eternal persons like the state, 

 and not to people who have the natural desire 

 to increase their property by their labor. For- 

 estry is, as the Germans term it, kapital-intensiv, 

 and arbeits-extensiv — business, i. e., relying to a 

 large extent on capital, with small chance of in- 

 creasing the earnings by intensive application of 

 labor. Especially for timber purposes it re- 

 quires large areas in one hand, a persistent 

 system of management and a ' wholesale' or- 

 ganization. Small space and little light are 

 given on the difficult and complex question of 

 rotation {principe de V exploitabilite ou eqoque 

 de la recolte) — i. e., the length of time to which 

 it is desirable to allow the crop to grow — when 

 to cut the crop. This problem is sui generis in 

 forestry, unknown to other industries, and as 



the author very wisely points out, requires a . 

 diffisrent solution according to whether the 

 state, with its long existence and providential 

 functions, or a private owner is concerned. 

 Since to a certain point ' the value of a tree 

 grows at least as the cube of the diameter,' 

 from the standpoint of the financier the harvest 

 time would have arrived when this value is at 

 a maximum, if other calculations, namely, in- 

 terest on investment, cost of production, etc., 

 to be charged with compound interest, did not 

 vitiate this simple device. The author con- 

 cludes that ' every harvest of old timber is 

 economically or financially a bad operation' 

 which contemplation leads to short rotations, 

 hence the production of heavy timber is not for 

 private enterprise, which thesis the author sup- 

 ports by examples. Most space is given to the 

 consideration of the ' felling budget ' {offre 

 raisonne) in a sustained-yield management 

 which the author calls with a new term ' pos- 

 sibilitS en fertilite ' — i. e., a management which 

 only reaps the amount annually accumulating 

 (revenue) if the soil is properly stocked with a 

 wood capital {valeur generatrice). 



We learn here to distinguish financially be- 

 tween two distinct values, which may attach 

 to one and the same forest property, namely, 

 the realizable (sale) value [valeur de realiza- 

 tion) based upon what can be realized at once 

 by a crude exploitation of the standing timber, 

 and the investment value (valeur de placement) 

 based upon what can be continuously realized 

 from the property by a forest management, a 

 distinction which will only gradually vanish, 

 the author expects, when the old natural 

 woods have vanished or the State has hold of 

 them. The same expectations are in place in 

 the United States, notwithstanding the sanguine 

 assertions of enthusiasts. 



B. E. Feknow. 



Technic of Mechanical Drafting. By C. W. 



Keinhaedt. (Pub. by Engineering News 



Co.) 



Mechanical draftsmen and teachers of graph- 

 ics may well add to their working libraries 

 this volume, in which the chief draftsman of 

 the Engineering News gives to the profession 

 the 'wrinkles,' 'short cuts' and methods in 



