The mental process by which certain gifted arithmetical computers reach almost in an instant the results of the most complicated calculations is a psychological problem of great interest, which has never been investigated. No more promising subject for the investigation could ever have been found than Safford, and I greatly regret having lost all opportunities to solve the problem. What was of interest in Safford's case was the connection of this faculty with other remarkable mental powers of an analogous but yet different kind. He had a remarkable faculty for acquiring, using, and reading languages, and would have been an accomplished linguist had he turned his attention in that direction. He was a walking bibliography of astronomy, which one had only to consult in order to learn in a moment what great astronomers of recent times had written on almost any subject, where their work was published, and on what shelf of the Harvard Library the book could be found. But the faculty most closely connected with calculation was a quickness and apprehension of vision, of which the following is an example:—
About 1876 he visited the Naval Observatory in Washington for the first time in his life. We wanted a certain catalogue of stars and went together into the library. The required catalogue was on one of a tier of shelves containing altogether a hundred, or perhaps several hundred volumes. "I do not know whether we have the book," said I, "but if we have, it is on one of these shelves." I began to go through the slow process of glancing at the books one by one until my eyes should strike the right title. He stood back six or eight feet and took in all the shelves seemingly at one glance, then stepped forward and said, "Here it is." I might have supposed this an accident, but that he subsequently did practically the same thing in my office, selecting in a moment a book we wanted to see, after throwing a rapid glance over shelves containing perhaps a hundred volumes.
An example of his apprehension and memory for numbers was narrated by Mr. Alvan Clark. When the latter had completed one of his great telescopes for the University of Chicago, Safford had been named as director, and accompanied the three members of the firm to the city when they carried the object glass thither. On leaving the train all four took their seats in a hotel omnibus, Safford near the door. Then they found that they had forgotten to give their baggage checks to the expressman; so the other three men passed their checks to Safford, who added his own and handed all four to the conductor of the omnibus. When it was time for the baggage to come to the hotel, there was such a crowd of new arrivals that the attendants could not find it. The hotel clerk remarked on inquiry, "If I only knew the numbers of your checks, I would have no difficulty in tracing your trunks." Safford at once told off the four numbers, which he had read as he was passing the checks to the conductor.
The great fire practically put an end to the activity of the Chicago Observatory and forced its director to pursue his work in other fields. That he failed to attain that commanding position due to his genius is to be ascribed to a cause prevalent among us during all the middle part of the century; perhaps that from which most brilliant intellects fail to reach eminence: lack of the power of continuous work necessary to bring important researches to a completion.
Another great intellect of the office was Chauncey Wright. If Wright had systematically applied his powers, he might have preceded or supplanted Herbert Spencer as the great exponent of the theory of evolution. He had graduated at Harvard in 1853, and was a profound student of philosophy from that time forward, though I am not aware that he was a writer. When in 1858 Sir William Hamilton's "Lectures on Metaphysics" appeared, he took to them with avidity. In 1859 appeared Darwin's "Origin of Species," and a series of meetings was held by the American Academy, the special order of which was the discussion of this book. Wright and myself, not yet members, were invited to be present. To judge of the interest it is only necessary to remark that Agassiz and Gray were the two leading disputants, the first taking ground against Darwin, the other in his favor. Wright was a Darwinist from the very beginning, explaining the theory in private conversation from a master's point of view, and soon writing upon it in the "North American Review" and in other publications. Of one of his articles Darwin has been quoted as saying that it was the best exposition of his theory that had then appeared. After his untimely death in 1875, Wright's papers were collected and published under the title of "Philosophical Discussions." [1] Their style is clear-cut and faultless in logical form, yet requiring such close attention to every word as to be less attractive to the general reader of to-day than that of Spencer. In a more leisurely age, when men wanted to think profoundly as they went along in a book, and had little to disturb the current of their thoughts, it would have commanded wide attention among thinking men.
A singular peculiarity which I have sometimes noticed among men of intelligence is that those who are best informed on the subject may be most reckless as regards the laws of health. Wright did all of his office work in two or three months of the year. During those months he worked at his computations far into the hours of the morning, stimulating his strength with cigars, and dropping his work only to take it up when he had had the necessary sleep. A strong constitution might stand this for a few years, as his did. But the ultimate result hardly needs to be told.
Besides the volume I have mentioned, Wright's letters were collected and printed after his death by the subscription of his friends. In these his philosophic views are from time to time brought out in a light, easy way, much more charming than the style of his elaborate discussions. It was in one of his letters that I first found the apothegm, "Men are born either Platonists or Aristotelians," a happy drawing of the line which separates the hard-headed scientific thinker of to-day from the thinkers of all other classes.
William Ferrell, a much older man than myself, entered the office about the same time as I did. He published papers on the motions of fluids on the earth's surface in the "Mathematical Monthly," and became one of the great authorities on dynamic meteorology, including the mathematical theory of winds and tides. He was, I believe, the first to publish a correct theory of the retardation produced in the rotation of the earth by the action of the tides, and the consequent slow lengthening of the day.
James Edward Oliver might have been one of the great mathematicians of his time had he not been absolutely wanting in the power of continuous work. It was scarcely possible to get even his year's office work out of him. Yet when I once wrote him a question on certain mathematical forms which arise in the theory of "least squares," he replied in a letter which, with some developments and change of form, would have made a worthy memoir in any mathematical journal. As a matter of fact, the same thoughts did appear some years after, in an elaborate paper by Professor J. W. L. Glaisher, of England, published by the Royal Astronomical Society.
Oliver, who afterward became professor of higher mathematics at Cornell University, was noted for what I think should be considered the valuable quality of absent-mindedness. It was said of him that he was once walking on the seashore with a small but valuable gold watch loose in his pocket. While deep in thought he started a kind of distraction by picking up flat stones and skipping them on the water. Taking his watch from his pocket he skipped it as a stone. When I became well acquainted with him I took the liberty of asking him as to the correctness of this story. He could not positively say whether it was true or not. The facts were simply that he had the watch, that he had walked on the seashore, had skipped stones, missed the watch at some subsequent time, and never saw it again.