It was during the sessions of that assembly that the famous debate was waged for several days on the exciting question of negro slavery, and when some compromise resolutions were passed (for those were the days of compromise salves and plasters)--Dr.Cox rose and exclaimed, "Well, brethren, we have _capped Vesuvius_ for another year," But "Vesuvius" would not stay capped, and in a few years one of its violent eruptions sundered the "new school" church in twain.
Dr.Cox was a vehement opponent of slavery, and his church in Laight Street was assailed by a mob, and he was roughly handled.

In 1833 he was sent to England as the delegate to the British and Foreign Bible Society, and at their anniversary meeting he delivered one of the most brilliant speeches of his life.

He came into the meeting a perfect stranger, while Dr.Hamilton, of Leeds, was uttering a fierce invective against American slavery.

This aroused Dr.Cox's indignation, and when he was called on to speak he commenced with exquisite urbanity as follows: "My Lord Bexley, ladies and gentlemen! I have just landed from America.

Thirty days ago I came down the bay of New York in the steam tug _Hercules_ and was put on board of the good packet ship _Samson_--thus going on from strength to strength--from mythology to Scripture!" This bold and novel introduction brought down the house with a thunder of applause.