At seventeen Lincoln wrote a clear, neat, legible hand, was quick at figures and able to solve easily any arithmetical problem not going beyond the “Rule of Three.”  Mr. Arnold, noting these facts, says:  “I have in my possession a few pages from his manuscript ’Book of Examples in Arithmetic’ One of these is dated March 1, 1826, and headed ‘Discount,’ and then follows, in his careful handwriting:  ’A definition of Discount,’ ‘Rules for its computation,’ ’Proofs and Various Examples,’ worked out in figures, etc.; then ‘Interest on money’ is treated in the same way, all in his own handwriting.  I doubt whether it would be easy to find among scholars of our common or high schools, or any school of boys of the age of seventeen, a better written specimen of this sort of work, or a better knowledge of figures than is indicated by this book of Lincoln’s, written at the age of seventeen.”

In March, 1828, Lincoln went to work for old Mr. Gentry, the founder of Gentryville.  “Early the next month the old gentleman furnished his son Allen with a boat and a cargo of bacon and other produce with which he was to go to New Orleans unless the stock should be sooner disposed of.  Abe, having been found faithful and efficient, was employed to accompany the young man.  He was paid eight dollars per month, and ate and slept on board.”  The entire business of the trip was placed in Abraham’s hands.  The fact tells its own story touching the young man’s reputation for capacity and integrity.  He had never made the trip, knew nothing of the journey, was unaccustomed to business transactions, had never been much upon the river, but his tact and ability and honesty were so far trusted that the trader was willing to risk the cargo in his care.  The delight with which the youth swung loose from the shore upon his clumsy craft, with the prospect of a ride of eighteen hundred miles before him, and a vision of the great world of which he had read and thought so much, may be imagined.  At this time he had become a very tall and powerful young man.  He had reached the height of six feet and four inches, a length of trunk and limb remarkable even among the tall race of pioneers to which he belonged.

Just before the river expedition, Lincoln had walked with a young girl down to the river to show her his flatboat.  She relates a circumstance of the evening which is full of significance.  “We were sitting on the banks of the Ohio, or rather on the boat he had made.  I said to Abe that the sun was going down.  He said to me, ’That’s not so; it don’t really go down; it seems so.  The earth turns from west to east and the revolution of the earth carries us under; we do the sinking, as you call it.  The sun, as to us, is comparatively still; the sun’s sinking is only an appearance.’  I replied, ‘Abe, what a fool you are!’ I know now that I was the fool, not Lincoln.  I am now thoroughly satisfied that he knew the general laws of astronomy and the movements of the heavenly