402 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



biologist of a clear understanding of recent work on osmosis, on ionic 

 conductivities and on colloidal solutions will be readily understood by all 

 who have been brought face to face with the problems suggested by 

 a study of the living cell. 



We should, perhaps, advise the non-scientific reader to postpone his 

 reading of the first chapter, which deals with the " philosophical basis of 

 physical science," until he has finished the rest of the book. The author 

 succeeds in giving an account, which is at once accurate and easy to 

 follow, of such subjects as Liquefaction of Gases, Absolute Zero, Fusion 

 and Solidification, Solution, Ionization, Conduction of Electricity through 

 Gases, Cathode Eays, X Eays, Eadio-activity and the nature of Matter and 

 of the Ether. He ends with an admirable account of the work with the 

 camera and spectroscope, which has brought the stars, metaphorically, into 

 the laboratory of the physical chemist, The book contains portraits of 

 Kelvin, Gibbs, Van 't HofY and J. J. Thomson. Two beautiful photo- 

 graphs represent actual apparatus used by J. J. Thomson and C. T. E. 

 Wilson, respectively, for their investigations into the constitution of the 

 atom, but the descriptions of these photographs would be more easily 

 followed if outline diagrams of the same apparatus were given. There 

 are numerous diagrams and some very fine microphotographs of the 

 minute structure of metals. 



"The Geology of South Africa." By F. H. Hatch, Ph.D., and 

 G. S. Corstorphine, Ph.D. Ed. 2. 8vo., xvi + 389 pp. Maps. 

 (Macmillan, London, 1909.) 21s. net. 



An account of the conformation and rocks of British South Africa, 

 including the work of the most recent investigators is presented to the 

 reader. The account is well illustrated by numerous diagrams and half- 

 tone figures, and deals especially with the mineral wealth of South 

 Africa. 



"Flora of Cornwall." By F. Hamilton Davey, F.L.S. 8vo., 

 lxxxviii + 570 pp. (Chegwidden, Penryn, 1909.) 21s. net. 



Who will be the first to break away from the style of County Floras 

 that has been the vogue for the past fifty years, and give us a complete 

 county flora on ecological lines ? Excellent beginnings have been made 

 in a few parts of the country over comparatively small tracts, but none 

 have attempted to cover any very wide area embracing very variable 

 conditions. It is certain that the publication of such a flora would give 

 an enormous impetus to the study of botany in different parts of the 

 country, since it would give to many who have not yet realized the 

 change that has come over botanical study of recent years, a concrete 

 example of the kind of natural history work, which need not, and indeed 

 should not, be confined to plants, which awaits the doing. There is room 

 for much investigation into the ways of plants in their homes, and he 

 would be doing a good work who turns the thoughts of the amateur 

 botanist from the acquirement of a collection of dried plants to a more 

 intimate study of their ways of life. 



The present work makes no attempt at this, but will rank with the 

 best of its predecessors as a list of plants with their local distribution 



