On monday the 17th instant arrived here a French ship of about 350 tons; called the Mercury, commanded by Captain John Heraud, in 40 days from Nantes, having the following very valuable cargo on board. viz. 11,987 stand of arms, 1000 barrels of gunpowder, containing 50 ton weight, 11,000 flints, 57 bales, 4 cases, and 2 boxes woollens, linnens, &c. on account of the United States of America. —

The captain & passengers (among whom is a brigadier general & a captain of artillery) gives us the following most agreeable account of the situation of affairs there, which they say might be relied on, viz. That 40 sail of the line, including frigates, were then lying at Brest, all ready to proceed for sea; that the greatest preparations for War were making at every other port in the Kingdom; that Doctor Franklin was most graciously received by His Majesty and the Nobility in general; on which occasion great rejoicings were made, such as.bonfires, &c. which so disgusted Lord Stormont, that he was preparing to leave Paris. ー They also assert that it was generally believ'd in France the Russians would not come out to America but if they attempted it, they would be intercepted by the French Fleet. ー Many other vessels had sail'd (and many more preparing) for America, with military and ordnance stores, as well as large quantities of cloathing ー The dispatches which came by this Vessel, were sent off per express to Congress on her arrival.