REVIEWS AND NOTICES OF BOOKS. 123 



greatest importance to the prosperity of present and future 

 generations. We may quote the following and convincing 

 paragraph from page 6x6 where, speaking of deforestation in 

 the Appalachians, the author says, "The rain beats directly 

 upon the soil, the retarding influence of the ground-litter and 

 tree roots and trunks is withdrawn, and more rapid soil removal 

 occurs. When once these evil effects have been allowed to 

 take place mankind is deprived, practically for thousands and 

 even millions of years, of the favourable conditions that preceded 

 the epoch of destruction. In a hundred years man may achieve 

 such baneful results as nature will compensate only during a 

 geologic period of hundreds of thousands of years. Soil is a 

 resource of priceless value. Many glacial striae formed on 

 resistent rock during the last glacial epoch, roughly 60,000- 

 75,000 years ago, are still preserved as fresh as if they were 

 made but yesterday. In that time man has come up from the 

 cave and the stone hammer. Seventy thousand years is a very 

 short time for the development of a soil cover ; for man it means 

 a period so great that his mind can hardly appreciate it. The 

 earth as we find it in the geologic to-day must be treated with 

 care if the human race is to have a fair distribution of its wealth 

 in time. To the geologic mind there is something shocking in the 

 thought that a single lumber merchant may in fifty years deprive 

 the human race of soil that required 10,000 years to form." 



A characteristic feature of the book is the lavish number of 

 well-chosen and beautifully reproduced photographs, diagrams 

 and maps. Many references to original sources of the literature 

 bearing on the subject are given in footnotes, and a very useful 

 and comprehensive index is given at the end. 



The Artificial Production of Vigorous Trees. By Augustine 

 Henry, M.A., F.L.S., M.R.I. A. Journal of the Department 

 of Agriculture and Technical Instruction for Ireland, vol. xv. 

 No. I. 



If there had been no intervention by artificial means, and 

 plants had been allowed to reproduce themselves naturally, 

 it goes without saying that, chance hybrids excepted, to-day 

 we would have had none of the useful food and other plants we 

 possess, but only the weeds from which they sprang. 



