NOTICES OF BOOKS. 55 



phical point of view, a subject which extends into the second volume. 

 This is followed by the second main division, entitled Botanical Geo- 

 graphy ^ that is, the study of the diflFerent countries of the globe viewed 

 with regard to their vegetation. The work is concluded with a chapter 

 on general results, and an Appendix indicating the directions in which 

 researches should be pursued by those desirous of advancing the study 

 of the Geography of plants. 



To give any adequate review of a work so comprehensive and ela- 

 borate as this, is obviously quite bey o ad both the scope and the func- 

 tion of the * Journal of Botany/ We believe however that a resume 

 of the contents of the various chapters it contains will be very accep- 

 table to our own readers, no less than to those who propose making a 

 special study of the work itself. They are as follows : 



Book I. Preliminary observations on the rationale of the action of 

 Temperature, Light, and Humidity. 



Chapter 1. Plants in relation to their surrounding physical condi- 

 tions. 



Chapter 2. Upon some of the eifects of Temperature and Light upon 

 plants, and upon several methods of measuring the influence of these 

 agents. — In this chapter a succession of subjects are treated as se- 

 parate articles, in more or less detail. Of these the most important 

 are, — on the temperature of the soil and of the air at certain distances 

 from it ; on the direct eflFect of the sun's rays ; on the effects of low 

 temperatures and of high temperatures, whether such are regarded as 

 having no eflFect or as being absolutely injurious ; on the effect that is 

 immediately induced by the accession of a favourable amount of tem- 

 perature; on variations of temperature; on the combined effects of tem- 

 perature and the clearness of the sky ; on the observations necessary 

 for obtaining directly the sums of the temperatures above that degree 

 which is necessary for the performance of the ordinary functions of the 



species. 



Throughout the above-mentioned articles are scattered a multitude 

 of tables of temperature, sunlight, and registers of the effects of these 

 elements upon the distribution of wild and cultivated herbs, shrubs, 

 and trees ; also tables of the mean and extreme temperatures of ra^my 

 places on the surface of the globe, and the comparison of these with 

 one another ; on the relation of elevation to latitude and temperature ; 

 .of light and shade to germinating seeds, etc. 



