FRAGMENTS OF SCIENCE. 



141 



as he could draw well he was ordered to 

 decorate the mausoleum of the Mahdl, and 

 this pleased the women of the Khalifa so 

 much that they petitioned the latter for his 

 liberation. It is also said that he has writ- 

 ten Arabic books and illustrated them. The 

 latter part of his twelve years' detention ap- 

 pears to have been less onerous, as after the 

 escape of Slatin he had to be interpreter 

 to the Khalifa and translator of European 

 newspapers which the ruler of the Soudan 

 received regularly. It is to the credit of the 

 Khalifa Abdullahi that not one of the 

 Christian prisoners received a hurt on the 

 approach of the Anglo-Egyptian forces. It 

 is expected that a narrative of his experience 

 in the Soudan will be shortly published by 

 Dr. Neufeld." 



Natural Selection and Fortuitous Varia- 

 tion — The three principal objections urged 

 against Darwin's theory of natural selection 

 were stated by Prof. W. F. R. Weldon, in 

 his presidential address to the Section of 

 Zoology and Physiology of the British Asso- 

 ciation, as being that the species of animals 

 we know fall into orderly series for the 

 selection of which purely fortuitous varia- 

 tions can not be supposed to afford opportu- 

 nity ; that minute structural variations can 

 not be supposed to affect the death-rate so 

 much as the theory requires they should, 

 while many of the characters by which spe- 

 cies are distinguished appear to us so small 

 and useless that they can not be supposed to 

 affect the chance of survival at all ; and that 

 the process of evolution by natural selection 

 is so extremely slow that the time required 

 for its operation is longer than the extreme 

 limit of time given by estimates of the age 

 of the earth. The first of these objections 

 the speaker alleged to be due to a misunder- 

 standing of words ; we regard as fortuitous 

 what we do not understand ; and he proceeded 

 to explain how what we call chance may be 

 shown, especially by a method developed by 

 Professor Pearson, to be a real and important 

 factor. To the other two objections Pro- 

 fessor Weldon opposed the results of ob- 

 servations of his own and of Mr. Herbert 

 Thompson on the small shore crabs ( Carci- 

 nus mcenas) at Plymouth Beach. " In these 

 crabs small changes in the size of the fron- 

 tal breadth do, under certain circumstances, 



affect the death-rate ; and the mean frontal 

 breadth among this race of crabs is, in fact, 

 changing at a rate sufficiently rapid for all 

 the requirements of a theory of evolution." 

 In conclusion, he said : " I hope I have con- 

 vinced you that the law of chance enables 

 one to express easily and simply the fre- 

 quency of variations among animals, and I 

 hope I have convinced you that the action of 

 natural selection upon such fortuitous varia- 

 tions can be experimentally measured, at 

 least in the only case in which any one has 

 attempted to measure it. I hope I have 

 convinced you that the process of evolution 

 is sometimes so rapid that it can be observed 

 in the space of a very few years." The 

 whole difficulty of natural selection, he 

 added, is a quantitative difficulty ; and he 

 insisted upon the need of observations and 

 measurements of the rates of variation. 



The Interior of Canada. — The country 

 between Lake St. John and James Bay is 

 under survey by the Department of Coloni- 

 zation and Mines of Quebec, in furtherance 

 of a scheme for a transcontinental railroad 

 to tap the Hudson Bay country and Lake 

 Winnipeg. As to the commercial advan- 

 tages of a railway center established at the 

 head of James Bay or at the limit of tide 

 water on the Nottaway River, Mr. O'Sullivan, 

 the surveyor, shows that the shore line of 

 Hudson and James Bay, following the east 

 coast from the mouth of the Nottaway to 

 the southern entrance to Hudson Strait, 

 measures, in a line running due north, eight 

 hundred miles, or about the same distance 

 as the former point is north of the city of 

 Washington ; and the western shore line, 

 measured in the same way to Rowe's Wel- 

 come, is about sixteen hundred miles, while 

 the area inclosed amounts to more than 

 three hundred and fifty thousand square 

 miles. While Hudson Strait is blocked 

 with ice during nine months of the year, the 

 bay itself is navigable from June till Novem- 

 ber, and James Bay is generally open early 

 in May. All the large rivers — the Albany, 

 Moose, Hannah, Nottaway, Rupert, Main, and 

 Big Rivers — converge along these shores, and 

 the forest wealth of the thousands of miles 

 drained by these and lesser rivers can be 

 concentrated at the mouth of the Nottaway or 

 Rupert. The land along the line from Lake 



