When he was sixteen years old, it became a question to what business he should devote himself.—­There was a prospect of obtaining a situation for him in a store at Philadelphia; and for that purpose it was deemed expedient that he should take up his abode for a while with his maternal uncle, whose house he had been so fond of visiting in early boyhood.  He did not succeed in obtaining the situation he expected, but remained in the city on the look-out for some suitable employment.  Meanwhile, he was very helpful to his uncle, who, finding him diligent and skillful, tried to induce him to learn his trade.—­It was an occupation ill-adapted to his vigorous body and active mind; but he was not of a temperament to fold his hands and wait till something “turned up;” and as his uncle was doing a prosperous business, he concluded to accept his proposition.  About the same time, his beloved cousin, Joseph Whitall, was sent to Trenton to study law.  This was rather a severe trial to Isaac’s feelings.  Not that he envied his superior advantages; but he had sad forebodings that separation would interrupt their friendship, and that such a different career would be very likely to prevent its renewal.  They parted with mutual regret, and did not meet again for several years.

When Isaac bade adieu to the paternal roof, his mother looked after him thoughtfully, and remarked to one of his sisters, “Isaac is no common boy.—­He will do something great, either for good or evil.”  She called him back and said, “My son, you are now going forth to make your own way in the world.  Always remember that you are as good as any other person; but remember also that you are no better.”  With this farewell injunction, he departed for Philadelphia, where he soon acquired the character of a faithful and industrious apprentice.

But his boyish love of fun was still strong within him, and he was the torment of all his fellow apprentices.  One of them, named William Roberts, proposed that they should go together into the cellar to steal a pitcher of cider.  Isaac pulled the spile, and while William was drawing the liquor, he took an unobserved opportunity to hide it.  When the pitcher was full, he pretended to look all around for it, without being able to find it.  At last, he told his unsuspecting comrade that he must thrust his finger into the hole and keep it there, while he went to get another spile.  William waited and waited for him to return, but when an hour or more had elapsed, his patience was exhausted, and he began to Halloo!—­The noise, instead of bringing Isaac to his assistance, brought the mistress of the house, who caught the culprit at the cider-barrel, and gave him a severe scolding, to the infinite gratification of his mischievous companion.