Professor W. H. Pickering attests to the importance of a steady atmosphere in studying the Moon from a station in Jamaica, when he says that, with a five inch refractor, he was able to detect minute details which were not revealed by the far larger telescopes at Harvard University.
Mr. W. D. Barbour, President of the Leeds Astronomical Society, using his four inch achromatic, says: "In one of those brief intervals of atmospheric steadiness I saw distinctly a number of well-known markings," the names of which he gives. Dr. Phil. Fauth, using a seven inch refractor, made sixty-three drawings of Mars, showing in wonderful detail the canals, oases, etc. Mr. W. J. Lockyer, in London "Nature," testifies that "a keen and patient observer, sitting at the eyepiece of a comparatively small equatorially mounted telescope, if he makes his observations carefully, and with due regard to atmospheric conditions for good seeing, can do more useful and valuable work than one who has a large aperture at his command and employs it indifferently." Mr. E. Ledger, in speaking of Dawes, who made a remarkable map of Mars, says he was justly famed for the remarkable distinctness of his vision; he had detected and drawn a few lines which seemed to be identical to those of Schiaparelli.
In the authorities above quoted we have endeavored to show that a steady atmosphere, a persistent devotion to the work, accompanied by acute vision, and also a talent for observation, are all the factors needed, not only to confirm the remarkable discoveries of Schiaparelli and Lowell, but possibly to detect, at favorable moments, new features which have escaped the eyes of these keen observers.
At this point we cannot resist giving the words of Sir David Gill, Director of the Royal Observatory at the Cape of Good Hope. Professor S. W. Burnham, of the Lick Observatory, in reviewing a memoir entitled "Double Star Observations at the Cape of Good Hope," quotes as follows from the preface: "Sir David Gill, in speaking of the routine character of the work involved in the investigation, says: 'There is no instance, as far as I know, of a long and valuable series of double star discovery and observation made by a mere assistant acting under orders. It is a special faculty, an inborn capacity, a delight in the exercise of exceptional acuteness of eyesight and natural dexterity, coupled with the gift of imagination as to the true meaning of what he observes, that imparts to the observer the requisite enthusiasm for double star observing. No amount of training or direction could have created the Struves, a Dawes, or a Dembowski. The great double star observer is born, not made, and I believe that no extensive series of double star measurement will ever emanate from a regular observatory, through successive directorates, unless men are specially selected who have previously distinguished themselves in that field of work, and who were originally driven to it from sheer compulsion of inborn taste.'" If the reader will substitute the words planetary markings for double star in the above quotation from Sir David Gill's report, he will understand why we have ventured to italicise certain lines, and will appreciate their significance. In no stronger or truer words could one have emphasized the conditions involved in a critical study of the surface features of Mars.
In the experience of an astronomer, it is not an unusual occurrence that an object in the heavens, fairly conspicuous, remains unseen until by some lucky chance an observer sweeping the sky picks it up, and, having determined its position, it is promptly found by others. Professor H. H. Turner, in his "Astronomical Discovery of the Nineteenth Century," says: "It is a common experience in astronomy that an observer may fail to notice in a general scrutiny, some phenomenon which he can see perfectly well when his attention is called to it; when a man has made a discovery, and others are told what to look for, they often see it so easily that they are filled with amazement and chagrin that they never saw it before."
In the Rev. T. W. Webb's interesting book on "Celestial Objects for Common Telescopes," a reminiscence of the author is given by a friend in which the following is related as illustrating the varying ability of observers in seeing. "A curious instance of difference of vision was well illustrated one superb evening when Mr. Webb and the writer were observing Saturn with the nine and a half inch refractor at Hardwick. Mr. Webb saw distinctly the division in the outer ring which the writer could not see a trace of, while the writer picked up a faint point of light which afterwards turned out to be Enceladus (a satellite) which Mr. Webb could not see."
In my brief observation of Mars I probably might have made out many more details if I had permitted Mr. Lowell to tell me what to see, and where to look for them on the disk. This I would not allow him to do, nor did I study any of the numerous drawings in his own work, or the original memoirs of Schiaparelli, or other works containing drawings of Mars in his library. I would not learn the names of any of the regions, or canals, nor with a single exception do I know them now. Only when I had finished my last night's observations, did Mr. Lowell take my drawings and write out a list of the various canals, oases, etc., which I had made out. Thus, unaided, I drew simply what was plainly evident, though many other details flashed out for a second, which were not recorded, simply because I did not see them often enough to be sure of their precise position on the disk.
Mr. Lowell points out one of the reasons why so many observers and astronomers have not seen the canals. In the third volume of the "Annals of the Lowell Observatory" he refers to a certain series of observations of Mars, made in 1894, and says: "Not only was there no sign of a canal, but even the main markings showed disheartingly indefinite." "This vacancy of expression was due to the Martian date." "It was the very nick of time to see nothing, for the part of the planet most presented to the Earth was then at the height of the dead season, and in this fact lies the key to much past undetection and present unbelief in the phenomenon of the canals."