28 NATURAL SCIENCE. July, 



boundary line of the " Cape " affects all our numeric results with 

 large plus and minus possibilities of error. 



The first and principal botanic gain, therefore, from the voyage 

 of the " Challenger " has been the Report on Insular Floras, by W. 

 B. Hemsley. It is not easy to epitomise his results shortly ; one 

 general result is the extent to which he has got rid of previously 

 admitted anomalies. We find, for instance, in some large genus, a 

 multitude of closely - allied species dotted about in the most 

 " anomalous " manner in various oceanic islands and their nearest 

 continents. But, as Mr. Hemsley observes, when all the material 

 comes into the hands of one competent man, he unites some species, 

 refers some specimens differently, and, finally, brings out a perfectly 

 clear and consonant result. Mr. Wallace found the vegetable pro- 

 ductions of Madagascar to be less like those of Africa than those of 

 England are to those of Japan. The result of fuller knowledge is 

 that the Madagascar flora is much more closely allied to that of 

 Africa than to that of Asia or Australia ; the ratio of similarity 

 between the flora of Madagascar and that of any other continent 

 follows the law of the inverse square pretty closely ; if it did not we 

 should have to look for prevalent winds or permanent oceanic 

 currents to explain the anomaly. We may almost venture to write 

 "human ignorance " in lieu of "anomalies in distribution." If we knew 

 all the geologic history in addition to the causes at work, we ought 

 to be able thereout to arrive at the existing distribution ; the 

 explaining away of an anomaly is the triumph of science. Hemsley 

 has got rid of some formerly-received generalisations that formed 

 very broad anomalies, and great obstacles to real progress. Thus it 

 was believed that, in insular floras, the proportion of endemic 

 species and of endemic genera was larger than in any continental 

 areas. This it appears is not the case ; in the flora of West 

 Australia, or of the Cape, the endemic character of the flora is as 

 strongly marked as in St. Helena or the Sandwich Isles. 



One good step leads to another ; Moseley's devoted labours led 

 to Hemsley's Insular Floras. This has influenced numerous researches 

 in the same field by H. O. Forbes, Guppy, Prain, Treub, J, Kirk, 

 Cheeseman, Vasey, Rose, Christ, Bolle, Urban. The literature has 

 already attained voluminous proportions. 



One moral suggests itself, viz., that every future scientific 

 expedition must have with it either a botanic specialist or a naturalist 

 of the wide views and power of work of Moseley — such a man may 

 be difficult always to find. But even Moseley could have given but a 

 fraction of his mind to a subject more than sufficient to occupy 

 completely a good all-round botanist. The investigation of insular 

 floras has now advanced so far that it is no longer satisfactory to set 

 one man to collect, and another man to work up, tabulate, discuss 

 and infer in the herbarium at home ; the man who stands on the 

 shore of the oceanic island should be himself master of his subject — 



