REV. JOHN O. CHOULES, recently pastor of a Baptist Church at New Bedford, Massachusetts, now of Buffalo, New York, made substantially the following statement in a speech in Boston. "While attending the Baptist Triennial Convention at Richmond, Virginia, in the spring of 1835, as a delegate from Massachusetts, I had a conversation on slavery, with an officer of the Baptist Church in that city, at whose house I was a guest. I asked my host if he did not apprehend that the slaves would eventually rise and exterminate their masters. "Why," said the gentleman, "I used to apprehend such a catastrophe, but God has made a providential opening, a _merciful safety valve_, and now I do not feel alarmed in the _prospect_ of what is coming. 'What do you mean,' said Mr. Choules, 'by providence opening a merciful safety valve?' Why, said the gentleman, I will tell you; the slave traders come from the cotton and sugar plantations of the South and are willing to buy up more slaves than we can part with. We must keep a stock for the purpose of _rearing_ slaves, but we part with the most valuable, and at the same time, the most _dangerous_, and the demand is very constant and likely to be so, for when they go to these southern states, the average existence Is ONLY FIVE YEARS!" Monsieur C.C. ROBIN, a highly intelligent French gentleman, who resided in Louisiana from 1802 to 1806, and published a volume of travels, gives the following testimony to the over-working of the slaves there: "I have been a witness, that after the fatigue of the day, their labors have been prolonged several hours by the light of the moon; and then, before they could think of rest, they must pound and cook their corn; and yet, long before day, an implacable scold, whip in hand, would arouse them from their slumbers. Thus, of more than twenty negroes, who in twenty years should have doubled, the number _was reduced to four or five_."