Lincoln, so far, had studied human beings and law. He knew nothing about mathematics, much less about surveying, probably not more than he knew about military tactics when he was elected captain. But he knew he could learn what any one else had learned. He bought a book on surveying and stayed with it almost day and night. He borrowed wherever he could hear of a book on surveying. In six weeks he had mastered the subject so that the many surveys he afterward made were never disputed and were always found to be correct. It is said that he was too poor at first to buy a surveyor's chain and so used a grapevine. But even a grapevine in the hands of Lincoln told the truth about measurements, and the town of Petersburg, Illinois, is proud of having been surveyed and laid out by Lincoln. III. OUT OF THE WILDERNESS PATHS INTO THE GREAT HIGHWAY The Great Teacher in his "Sermon on the Mount," said, "Blessed are they that hunger and thirst after righteousness, for they shall be filled." If that destitute boy had not hungered and thirsted after right knowledge, the whole history of America, after his time, would have been different. But what boy would read, or what other boy ever did read such a book as the "Revised Statutes of Indiana?" To be sure, not the boy who is most interested in getting merely the most pleasure out of life, but the one who has a great desire to be useful and worthwhile in the world. The next book that deeply impressed his career and probably had most to do with developing him to influence profoundly the history of our country was that beginning of every lawyer's life, "Blackstone's Commentaries." This is the way Lincoln tells it himself: "One day a man, who was migrating to the West, drove up in front of my store with a wagon which contained his family and household plunder. He asked me if I would buy an old barrel, for which he had no room in his wagon, which he said contained nothing of value. I did not want it, but, to oblige him, I bought it, and paid him, I think, a half-dollar. Without further examination I put it away in the store, and forgot all about it. Some time after, in overhauling things, I came upon the barrel, and, emptying it upon the floor to see what it contained, I found at the bottom of the rubbish a complete edition of Blackstone's Commentaries. I began reading those famous works and the more I read the more intensely interested I became. Never in my whole life was my mind so thoroughly absorbed." [Illustration: First Inauguration of Lincoln as President.] It was that interest which made the man and the great historical character of Lincoln. One lives according to his interest in life, and the meaning realized in him as humanity.