Works on Biology, etc. 



separated, gave rise to considerable coutroversy. Wal- 

 lace's tiiial estimate of the work stands : " No one is more 

 aware than myself of the defects of the work, a consider- 

 able portion of which are due to the fact that it was writ- 

 ten a quarter of a century too soon — at a time when both 

 zoological and palaeontological discovery were advancing 

 with great rapidity, while new and improved classifica- 

 tions of some of the great classes and orders were in con- 

 stant progress. But though many of the details given in 

 these volumes would now require alteration, there is no 

 reason to believe that the great features of the work and 

 general principles established by it will require any im- 

 portant modification . " * 



About this time he wrote the article on " Acclimatisa- 

 tion " for the "Encyclopaedia Britannica"; and another 

 on " Distribution-Zoology " for the same work. As Presi- 

 dent of the Biological Section of the British Association 

 he prepared an address for the meeting at Glasgow; wrote 

 a number of articles and reviews, as well as his remark- 

 able book on " Miracles and Modern Spiritualism." In 

 1878 he published " Tropical Nature," in which he gave 

 a general sketch of the climate, vegetation, and animal life 

 of the equatorial zone of the tropics from his own observa- 

 tions in both hemispheres. The chief novelty was, accord- 

 ing to his own opinion, in the chapter on " climate," in 

 which he endeavoured to show the exact causes which 

 produce the difference between the uniform climate of the 

 equatorial zone, and that of June and July in England. 

 Although at that time tee receive actually more of the light 

 and heat of the sun than does Java or Trinidad in Decem- 

 ber, yet these places have then a mean temperature very 

 much higher than ours. It contained also a chapter on 

 humming-birds, as illustrating the luxuriance of tropical 

 » " My Life," pp. 97-8. 

 11 



