This was the beginning of a friendship which appears to have been the only one of its kind Lincoln ever had. Late in life, with his gifted private secretaries, with one or two brilliant men whom he did not meet until middle age, he had something like intimate comradeship. But even they did not break the prevailing solitude of his inner life. His aloofness of soul became a fixed condition. The one intruder in that lonely inner world was Speed. In the great collection of Lincoln's letters none have the intimate note except the letters to Speed. And even these are not truly intimate with the exception of a single group inspired all by the same train of events. The deep, instinctive reserve of Lincoln's nature was incurable. The exceptional group of letters involve his final love-affair. Four years after his removal to Springfield, Lincoln became engaged to Miss Mary Todd. By that time he had got a start at the law and was no longer in grinding poverty. If not yet prosperous, he had acquired "prospects"--the strong likelihood of better things to come so dear to the buoyant heart of the early West. Hospitable Springfield, some of whose best men had known him in the Legislature, opened its doors to him. His humble origin, his poor condition, were forgiven. In true Western fashion, he was frankly put on trial to show what was in him. If he could "make good" no further questions would be asked. And in every-day matters, his companionableness rose to the occasion. Male Springfield was captivated almost as easily as New Salem. But all this was of the outer life. If the ferment within was constant between 1835 and 1840, the fact is lost in his taciturnity. But there is some evidence of a restless emotional life.