XIV 



PREFACE. 



This volume, on the effects of forests on the humidity of the 

 atmosphere and of the ground, follows in the series, supplying 

 illustrations of the reasonableness of the suggestion made in regard 

 to the conservation and extension of forests, as a subordinate 

 means of arresting and counteracting the desiccation and aridity 

 of the country. 



And early in the, present year was published a volume entitled 

 "Eeboisement in France: or, Eecords of the replanting of the, 

 Alps, the C6vennes, and the Pyrenees with trees, herbage, and. 

 bush, with a view to arresting and preventing the destructive 

 consequence and effects of torrents." 



Should eucouragement offer, the publication of this volume wiU^ 

 be followed by the publication of a volume on the effects of 

 forests on -the temperature of a country, and the correlation of 

 humidity and temperature in- meteorological phenomena; a volume 

 on''the chemistry of vegetation, and the effects thereby produced 

 on the salubrity of a climate ; and a compilation of official docu- 

 ments, showing what arguments for the conservation and exten- 

 sion of forests have been submitted to the consideration' of 

 legislative and sciciitifio bodies in different countries, in view of 

 the meteoi:oiogical effects of forests, — and what measures h^ve been 

 adapt,ed in ■ yiew of these to secure more extensively for the benefit 

 of man the meteor-olqgical benefits which may be thus produced. 



Haddington, December 1876. 



