4] DISPERSAL AND MIGRATION I27 



has observed such ' dirty ' floes in many places up to almost the 

 highest latitudes (the ice immediately around the North Pole appears 

 to be ' clean '). From the air, some of the browns and yellows of 

 these floes seem not far removed in colour-effect from some barren 

 arctic limestones — as the author and his pilot had occasion to remark 

 once in 1946 when flying over Foxe Basin and sighting an unexpected 

 island of limestone which turned out to be some 90 miles long and 

 nearly as wide. It was officially ' discovered ' two years later by 

 the Royal Canadian Air Force and added to the world's map as 

 ' Prince Charles Island ', being, with its neighbours which were also 

 noted on that 1946 occasion, evidently the last major land discovery 

 or confirmation to be made in the world. Subsequent exploration 

 failed to reveal any unexpected features of plant life. Until the 

 advent of general air travel not so long ago, many areas even in 

 comparatively low latitudes were difficult or at least tedious to visit. 

 But now in superb antithesis we are looking to other planets for 

 explorational opportunities, and the prospects of space travel are 

 advancing so rapidly that the author is prompted to guard himself 

 by remarking that the present volume is concerned purely with 

 vital phenomena as we know them on the Earth and in its immediately 

 surrounding atmosphere — regardless of any possibilities elsewhere. 



Further Consideration 



H. N. Ridley. The Dispersal of Plants throughout the World (Reeve, 

 Ashford, Kent, pp. xx + 744, 1930). A monument of usually 

 authoritative information on the methods and effectiveness of plant 

 dispersal, covering almost all aspects of the subject. Its author died 

 recently at well over 100 years of age, maintaining that such studies, 

 of which there are still not nearly enough, are fine preservers of life. 



Charles Darwin. The Origin of Species by means of Natural Selection, 

 sixth edition, with additions and corrections (Murray, London, 

 pp. xxi + 458, 1873). 



H. B. GUPPY. Plants, Seeds, and Currents in the West Indies and Azores 

 (Williams & Norgate, London, pp. xi + 531, 1917). A work of 

 wider implication than its title suggests. 



A. Kerner (von Marilaun), & F. W. Oliver. The Natural History of 

 Plants, vol. II, pp. 790 et seq. (Blackie, London, 1895). 



Sir E. J. Salisbury. The Reproductive Capacity of Plants (Bell, London, 

 pp. xi + 244, 1942). 



L. V. Barton. Seed Preservation and Longevity (Leonard Hill, London 

 — in press). 



C. T. Ingold. Dispersal in Fungi (Clarendon Press, Oxford, pp. 

 viii + 197, 1953). 



