238 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



information quoted are given. There is, however, no index of 

 contents and authors, and only, at the end of the book, a very 

 inadequate summary of each chapter. This is a pity, since 

 with a good index a book is made so much more accessible. It is, 

 of course, out of the question to attempt, in a brief space, to give 

 more than a general impression of a book of this size, or even 

 to draw attention to parts, here and there, which seem deserving 

 of special notice. The introductory chapter, commencing with a 

 general statement on the formation and constitution of forest 

 soils, is mainly taken up with an interesting comparison of the 

 properties and functions of forest soils and agricultural soils. 

 In this comparison it is at once made clear, in dealing with such 

 questions as the supply and importance of humus, the com- 

 position of soil-water and air, the improvement of soils, their rate 

 of exhaustion and manner of nutrition, etc., that fundamental 

 differences exist between the two categories of soils. These 

 differences are dealt with in subsequent chapters. 



One aspect of afforestation, given on page 6, and expressed in 

 the following sentence, seems worth quoting : — " Le boisement 

 est le seul procede que I'homme ait h. sa disposition pour 

 am^liorer sans aucuns frais — mais avec le concours du temps — 

 les sols de mauvaise qualite et les rendre aptes a la culture." 

 Further on in the book comes the terse statement, " C'est le sol 

 qui fait la foret." Certainly this emphasis on the soil is largely 

 justified in agriculture, but one is almost led to believe, from 

 earlier chapters, that moisture, warmth, elevation, sunlight, etc., 

 are the really dominating factors in forest growth, so that the 

 expression must not be taken too literally. 



It is of cardinal importance in afforestation to encourage the 

 production of humus of the right kind and thickness, for upon 

 this factor the supply and preservation of water and nitrogen, 

 the soil texture, and the supply of available mineral food 

 materially depend. It is then not surprising that the next nine 

 chapters are devoted to an elaborate treatment of the cotiverie 

 viorte or dead covering in all its varying aspects. Though 

 humus is an essential ingredient of agricultural soils, it is 

 manifestly of greater importance in the soils of the forest. 

 Perhaps chapter ix., which deals with the decomposition 

 of the couverte morte by eremacausis, is the most interesting. 

 Mention is here made of the work of Pasteur, Berthelot, 

 Schloesing, Muntz, De Saussure, Warington, Winogradsky, 



