He had a taste also for mechanics.  He conceived the idea of making a timepiece, a clock, and about the year 1770 constructed one.  With his imperfect tools, and with no other model than a borrowed watch, it had cost him long and patient labor to perfect it, to make the variation necessary to cause it to strike the hours, and produce a concert of correct action between the hour, the minute, and the second machinery.  He confessed that its regularity in pointing out the progress of time had amply rewarded all his pains in its construction.[613]

In 1773 Ellicott & Co. built flour-mills in a valley near the banks of the Patapsco River.  Banneker watched the mills go up; and, when the machinery was set in motion, looked on with interest, as he had a splendid opportunity of observing new principles of mechanism.  He made many visits to the mills, and became acquainted with their proprietors; and, till the day of his death, he found in the Ellicotts kind and helpful friends.

After a short time the Ellicotts erected a store, where, a little later, a post-office, was opened.  To this point the farmers and gentlemen, for miles around, used to congregate.  Banneker often called at the post-office, where, after overcoming his natural modesty and diffidence, he was frequently called out in conversations covering a variety of topics.  His conversational powers, his inexhaustible fund of information, and his broad learning (for those times and considering his circumstances), made him the connoisseur of that section.  At times he related, in modest terms, the difficulties he was constrained to encounter in order to acquire the knowledge of books he had, and the unsatisfied longings he still had for further knowledge.  His fame as a mathematician was already established, and with the increasing facilities of communication his accomplishments and achievements were occupying the thought of many intelligent people.

“By this time he had become very expert in the solution of difficult mathematical problems, which were then, more than in this century, the amusement of persons of leisure, and they were frequently sent to him from scholars residing in different parts of our country who wished to test his capacity.  He is reported to have been successful in every case, and, sometimes, he returned with his answers, questions of his own composition conveyed in rhyme.”

The following question was propounded to Mr. George Ellicott, and was solved by Benjamin Hallowell of Alexandria.

    “A Cooper and Vintner sat down for a talk,
    Both being so groggy, that neither could walk,
    Says Cooper to Vintner, ’I’m the first of my trade,
    There’s no kind of vessel, but what I have made,
    And of any shape, Sir,—­just what you will,—­
    And of any size, Sir,—­from a ton to a gill!’
    ‘Then,’ says the Vintner, ’you’re the man for me,—­
    Make me a vessel, if we can agree.