November 30, 1906.] 



SCIENCE. 



707 



chemist has one chance in four of being as 

 competent as a certain pathologist, a result 

 that would not be possible by direct compari- 

 son. The various factors vphich limit the ex- 

 actness of the method should be kept in mind, 

 but we have at least the beginning of a method 

 which with further effort can be made more 

 accurate. Similar methods can be applied to 

 comparing the value of performance in fields 

 even more diverse than the several sciences. 



IQ 



■+0 



to 



S-0 



100 



Fig. 2. Distribution of the thousand men of 

 science. 



In the accompanying curve — which is based 

 on substantially the same figures as are given 

 in table III., except that a man is given a 

 position only in the science in which he stands 

 the highest — is shown the distribution of the 

 thousand men of science. The 1,000 scientific 

 men are divided into ten groups, the range of 

 eminence or merit covered by each hundred 

 being proportional to the space it occupies on 

 the axis of the abscissas, and the number of 

 each degree of ability being proportional to 

 the ordinates. The range of merit covered 

 by each hundred becomes smaller and there 

 are more of each degree of merit as we pass 

 from the first to the second hundred and so 

 on for the first five hundred, after which the 

 differences become very small. The first hun- 

 dred men of science cover a range of merit 

 about equal to that of the second and third 

 hundreds together, and this again is' very 

 nearly equal to the range covered by the re- 

 maining seven hundred. The average differ- 



ences between the men in the first hundred are 

 about twice as great as between the men in 

 the second and third hundreds, and about 

 seven times as great as between the men in the 

 remaining groups. Or the differences among 

 the first hundred are almost exactly ten times 

 as great as among the last five hundred, who 

 differ but little among themselves. It would 

 be desirable to compare this distribution with 

 that of the normal probability integral and 

 with the salaries paid to scientific men, but 

 the data are not as yet at hand. 



J. McKeen Cattell. 

 Columbia Univeesity. 



NOTES ON ORGANIC CHEMISTRY. 



OPTICALLY ACTIVE COMPOUNDS WHICH CONTAIN 

 NO ASYMMETRIC ATOM. 



Optical activity, or the power of causing 

 deviation in the path of a ray of polarized 

 light, is shown by hundreds of organic com- 

 pounds, all of which contain one or more 

 asymmetric atoms of carbon, nitrogen, sul- 

 phur, etc. A carbon atom is asymmetric 

 when it is linked to four, and a nitrogen 

 atom when it is linked to five dissimilar atoms 

 or groups. The only exception to the above 

 connection of asymmetry and optical activity 

 is the compound inosit, which has the formula 



HOCH<CH(OH)CH(OHl>(,jjOjj 



and is said to exist in two modifications of 

 opposite activity. Quite recently a second 

 exception has been discovered by "W. Marck- 

 wald and R. Meth.^ Their starting point is 

 1-methylcyclohexanone- (4) , 



(4) 



CHsCH<CgCH CO, 



from which, by a few simple steps, they ob- 

 tain the corresponding acetic acid derivative. 

 This is called l-methylcyclohexylidene-(4)- 

 acetic acid, 



CH3CH< cI'ch' > ^ '• CHCOOH . 



By means of its chinchonine salts this acid is 

 resolved into two new acids of opposite, and 

 practically equal optical activity, just as is the 

 ^Ber. d. Chem. Ges., 39, 2404 (1906). 



