QUEBEC, December  2, 1790 Yesterday's post from Montreal, conveyed letters to several gentlemen in town, all corroboratiing the following extract.

" SIR, "I have to inform you by several letters received here on Saturday from Detroit, "we are informed the Americans, under General Sinclair, had been twice defeated, about the 19th ult. with the loss of from 500 to 600 men, by the Indians The Indians first attacked a body of 300 horse which they had drawn into a snare, and cut the whole of them off. In a second engagement, they were likewise victorious, having nearly killed as many. On account of which, Sinclair thought proper to retreat; and the last accounts state the Indians having divided themselves into small parties, had so harrassed him, that he was obliged to leave the wounded in the field--Sinclair lost his artillery, a cohorn, and grass-hopper. It is said the Indians are very much elated at their success, and that numbers were daily joining them, at their head quarters, about the Maimis towns--One Indian, it is said, killed 30 with his own hand.

"The Indians were extremely civil to the traders from Detriot, having assisted them, when they knew of the approach of the Americans, to remove their property to safety, except ammunition and arms. These are facts so well ascertained, that there does not remain the least doubt of them:

They may be attended with very serious and important consequences to the province, as I dare say, all will be imputed to the British for supplying these Indians with arms and ammunition.--In short, I would not be surprized to hear of an American army raising, to attack this country. * The loss is here specified, but other letters differing in number, we shall only say, the estimate in general does not appear considerable.

