SKETCH OF WILLIAM FERREL. 689 



that price. It was a light task to learn all that was in it." One 

 can not forbear to moralize over this intense desire for knowledge, 

 for what would not such a boy have learned with proper encour- 

 agement and opportunity ! It must be to these and the succeed- 

 ing years of hampered effort that Ferrel refers in a few sad words 

 at the close of his narrative : " Much of my time has been wasted, 

 especially the earlier part of it, because, not having scientific 

 books and scientific associations, I often had nothing on hand in 

 which I was specially interested." 



It may be said that Ferrel began his career as an investigator 

 in 1832, when on going out one day to work he noticed that the 

 sun was eclipsed. He had not known that such an event was to 

 occur, but it set him to thinking. He had somewhere learned the 

 cause of solar and lunar eclipses, but his materials for further 

 study were only a German calendar, such as farmers use, and a 

 copy of Adams's Geography, with an appendix giving problems 

 on the use of the globes. From these he found that the sun and 

 moon moved with unequal velocities in different parts of their 

 orbits, and that the fastest and slowest motions were at opposite 

 points. Of this he writes : " My theory was that the earth and 

 the moon moved with uniform velocity in circular orbits, and that 

 these orbits were eccentrically situated with regard to the sun 

 and earth. With regard to the moon's path, I knew that it crossed 

 the ecliptic, but I did not know at what angle, and I also at first 

 supposed that the node was fixed. At the beginning of the next 

 year, when the next calendar came to hand, I discovered from the 

 predicted eclipses that the node must recede. I saw from the 

 calendars that there was some cycle of nineteen years, and sus- 

 pected that this had something to do with the moon's node. This 

 would make the node recede about 19° in a year, as the next year's 

 eclipses seemed to require." Then, with the aid of some older cal- 

 endars, Ferrel, about at the age of sixteen, proceeded to make out 

 tables of the dates of eclipses in an empirical fashion, but he un- 

 fortunately assumed that the diameter of the earth's shadow was 

 constant. " Upon this assumption I spent a vast amount of time, 

 but could get no positions of the nodes or inclination of the orbit 

 which would satisfy the eclipses. The amount of study I gave to 

 the subject both day and night was very great, but I at last gave 

 the matter up in despair. Some time after I was at work one day 

 toward evening on the thrashing-floor, and saw the shadow of a 

 distant vertical plank against the wall ; I observed that it was 

 much smaller than the width of the plank, and the reason for it 

 occurred to me at once. I then saw the error of my assumptions 

 with regard to the earth's shadow in my eclipse investigations 

 and was now very anxious to go over again all my computations 

 with the true diameter of the earth's shadow, for, knowing the dis- 



TOL. XL. 17 



