THE issue of Science for November 23 contains an article by Prof. McKeen Cattell on the selection, and arrangement in order of merit, of a thousand American men of science. A table was compiled from lists of fellows of societies, biographical dictionaries, “Who's Who,” &c., of the numbers of persons engaged in each branch of science. It appears that chemists are the most numerous, in America at all events, forming 164 per 1000 of all scientific men, zoologists coming a close second with 155 per 1000. Anthropologists stand at the foot of the list with only twenty-three, but neither statisticians nor economists, it would seem, were taken into account. Ten leading representatives of each science were then asked to arrange in order of merit a certain number of students of that science, the numbers fixed being roughly proportionate to the totals in the table first compiled. The positions assigned by the different judges to every individual were averaged, and the probable error f the average position of each calculated. A general list, including representatives of all the sciences, was also compiled by interpolation, but neither this nor the separate lists are published. An interesting table is given showing the divergences between the ten judges in the case of psychology, as an illustration. The order of merit given by one of the judges is very much more accordant with the average order than those of the others, and they differ considerably inter Se, though more, if we understand the table rightly, in the case of those at the bottom of the list than of those towards the top. Of the first hundred scientific men on the list who are eligible, sixty-one are included among the ninety-seven members of the National Academy of Sciences. The discussion of the grades and probable errors is continued in Science for November 30, and in a third and concluding article in the issue for December 7 Prof. Cattell investigates the geographical distribution of American men of science, according to place of birth and place of residence. The figures as regards the former are extremely striking. The production or “birth-rate” of men of science per million of the population ranges from about 109 in Massachusetts—which stands far above the other States—and eighty-seven in Connecticut down to rates of only one or two in several of the southern States. It is argued that differences in stock can scarcely be great enough to account for this, and that accordingly the production of scientific men must be largely a matter of circumstance. As regards the place of residence, interesting tables are given showing the institutions with which the men of science taken into account are connected. The work forms part of an extended investigation which Prof. Cattell has now been conducting for some ten years, and on which he has published several previous memoirs.