rests not upon a difference of data, but upon a difference of logic. To my mind the enumeration of ages at death of any number of great men cannot prove unusual longevity unless we take into consideration and can determine the number of years which, on the average, a person must have lived in order to become a candidate for the class under consideration. The comparison with the average age (that is, the period of about thirty-five or more years) is not only false; it is essentially absurd; for it would become possible only if we had among poets, and painters, and musicians, and historians, and scientists, and generals a goodly number who succumbed to the diseases of early infancy, or to some of the ills that juvenile flesh is heir to.
It may be well to illustrate at this point just what conclusions may be drawn from the data which Mr. Thayer and other writers have presented. The first conclusion is that it takes a considerable length of time to become eminent—on the whole a very natural and comprehensible statement. And with regard to the astronomers previously mentioned it is even possible to go farther; for these astronomers have been divided into four degrees of eminence, and it is found that astronomers of the first rank are longer-lived than those of the second, and these in turn are longer-lived than those of the third class, and these in turn are longer-lived than those of the fourth class. Therefore, the author concludes, the greatest astronomers have been most favored with length of years, and adds, as practical advice, "Be an astronomer and live long." Now, of course, the true conclusion is that it takes longer to accomplish work which will entitle one to pre-eminence amongst astronomers than to do work which will only achieve moderate distinction. And the practical conclusion would read, "Live long enough to become great as an astronomer and you will probably, with the ordinary expectation of life, have a good chance of completing your three score and ten." In the same way Mr. Thayer's list of nineteenth-century celebrities might fairly be said to suggest the conclusion that in the present century one must already have labored for a goodly number of years before one's name would be selected by a student of the longevity of great men. So far, then, these facts have an interesting interpretation.
It may also be worth while to note that if all the men whose longevity is to be compared are of a comparable class (that is, comparable with regard to the attainment of years which they assume), then the longevity of different groups of celebrities may be compared with one another. Thus it is possible to compare the longevity of musicians with that of scientists (of about equal eminence), and according to Mr. Thayer*s lists the scientists lived ten years longer than the musicians. The same conclusion appears in my own study, in which the scientists appear amongst the longest-lived, and the musicians amongst the shortest-lived men of genius. This conclusion must not be pressed too far, but in a general way it certainly is a bit of evidence worthy of consideration as proving that distinguished scientists live longer than distinguished musicians. It would be wrong to draw rigid conclusions from comparisons of small groups, and therefore it is better to contrast the average age at death of the various men studied in as large and as general classes as possible; e. g., as men of thought, men of feeling and men of action. All of the studies with which I am acquainted point to the conclusion that men of thought live longer than those who achieve distinction through unusual qualities of their emotional natures.
We may now approach the question, whether or not it is possible to prove that the men of distinction of the nineteenth century are longer-lived or shorter-lived than their every-day contemporaries. It would be possible to do this had we statistics of the age at death of