March io, 192 i] 



NATURE 



49 



surveys in unexplored or virgin tracts such 

 as are to be found in Brazil, where the 

 author has had much experience. For com- 

 puting discharges, the well-known Chezy formula 



Fig. I. — Dovey Valley, showiag the river meandering from side to side of a broad, flat valley. From 

 " Practical River and Canal Kngineering." 



is quoted, but there is no reference to the classic 



expression of Ganguillet and Kiitter, or to the 



suggested adaptation of Chezy 's formula in a very 



compact form, put forward by Mr. Barnes a few 



years ago. Chap. v. treats of waterways (water- ' 



courses would be a better 



term), which are classified 



as torrents, torrential rivers, 



semi-torrential rivers, and 



smooth flowing rivers. 



Chap. vi. deals with floods, 



chap. vii. with water flow, 



and the two following 



chapters with river training 



and canalisation. Canals 



are left to the last, and are 



compressed within the limits 



of a single chapter. 



From the foregoing out- 

 line of the contents, and 

 from the fact that the book 

 contains only 1 19 pages of 

 matter in fairly large sized 

 print with numerous illus- 

 trations, it is evident that 

 the treatment of the subject 

 is necessarily general. In- 

 deed, the author disclaims 

 any attempt to include theo- 

 retical considerations in his 

 purview. The explanation 



of so important a subject as canal construction 

 within the compass of ten pages is obviously in- 

 sufficient for completeness. As a brief review, 

 "however, the book has the merit of being clear 

 NO. 2680, VOL. 107] 



and interesting, and the author's experiences in 

 Brazil and elsewhere yield a number of practical 

 hints of serviceable importance. 



The startling incident recorded on p. 21 of the 

 sudden invasion in clear 

 weather of a trekking camp 

 in Minas Geraes, Brazil, by 

 a torrent from a downpour 

 of rain on the hill summits 

 some few miles away gives 

 a vivid idea of the uncer- 

 tainties and vagaries of 

 rainfall in some districts. 

 However, it is not necessary 

 to seek an example so far 

 away as Brazil ; there was 

 quite recently a disastrous 

 instance of the same kind in 

 Lincolnshire when the town 

 of Louth was swept by a 

 flood without any warning. 

 The author dwells on the in- 

 fluence of vegetation in re- 

 gard to its effect on rainfall, 

 and says that in Brazil, as 

 in other countries, great 

 loss has been incurred 

 through the careless cut- 

 ting down of trees to 

 make way for the farmer. 

 He states that many extensive forests have dis- 

 appeared within the last fifty years, due to the 

 custom. of burning down a wooded area to form 

 new plantations as soon as the old, for lack 

 of care, have become exhausted. He believes 



Fig. 2.— Canal in sandstone cutting. From " Practical Kiver and Canal Engineering. 



that the lack of rain upon several districts in 

 Brazil is a direct consequence of this policy ; 

 this is an opinion which will, however, not com- 

 mand general acceptance. 



