November 30, 1906.] 



SCIENCE. 



703 



about ten times as much as men who are 

 about 5 ft. 8 in. tall, though the difference 

 in their height is only as 68 : 74. Even, though 

 we assumed the zero point to be where psy- 

 chological performance begins or at the sur- 

 vival minimum of human ability, we should 

 only obtain relative differences. 



The astronomers and the psychologists have 

 been used as illustrations. The number of 

 students of astronomy and of psychology in 

 the country does not differ greatly, and it is 

 assumed that they represent an equal range of 

 scientific merit. It is possible that it requires 

 more ability to be an astronomer than to be 

 a psychologist, and it is equally possible that, 

 in view of the larger endowments, longer his- 

 tory and more conventional problems, less 

 ability will suffice for the astronomer. The 

 curves of distribution might also vary; for 

 example, it might be relatively easier to be 

 an astronomer of moderate performance, but 

 more difficult to be a great astronomer. There 

 are indications of such differences, but the 

 data at hand do not disclose them with any 

 degree of certainty. 



There are 100 geologists and 100 botanists 

 on the list, who are about one fourth of all 

 the geologists and botanists of the country. 

 These are assumed to cover about the same 

 range of scientific merit as the astronomers 

 or the psychologists. The average difference 

 between the geologists would consequently be 

 about half that between the astronomers, and 

 the probable errors of position should theoret- 

 ically be about twice as large. The anthro- 

 pologists are the smallest class of scientific 

 men, numbering in all about ninety, of whom 

 20 are included in the thousand under con- 

 sideration. They are again assumed to cover 

 a range of performance equal to that of the 

 astronomers or geologists, the average differ- 

 ence between them being two and a half times 

 as great as between the astronomers or five 

 times as great as between the geologists. The 

 chemists are the most numerous class of scien- 

 tific men, 175 being included in the thousand. 

 There are 150 physicists, 150 zoologists, 80 

 mathematicians, 60 pathologists, 40 physiolo- 

 gists and 25 anatomists. 



In the accompanying table are given the 



GRADES AND PROBABLE ERRORS OF THE TWENTY MEN OF SCIENCE WHO STAND FIRST IN EACH 



OP THE SCIENCES. 



