The Sloop St. Peter, of New-York, under Dutch Colours, from St. Ustatia to Amsterdam with Tobacco, Sugar and Rum, is taken by the Dolphin Cutter, Capt. Miller, and brought into Cowes.

They write from Boston, that the Privateers yet at Sea are mostly small; but there are a great many on the Stocks, which will be soon launched, to carry from 16 to 24 Guns; and several Frigates are building, and some of them near finished, in different Parts on the Continent, for the public Service, which will mount from 36 to 44 Guns.

There is a very advantageous Trade carried on from New England, which in fact is at the general Risque, as they insure for each other; and although several of their Vessels are taken, they nevertheless find it very beneficial, as nine out of ten escape; and it is said the same good Fortune attends the Adventurers in other Colonies; the Value of the Vessels, and theCargoes taken from them is trifling, whereas those they take are worthmore in Proportion than ten to one. In short, their Success is so pleasing, that in consequence the Spirit for Privateering is so prevelant, that they intend the West-Indies, and other Parts, shall swarm with them next Winter.

Advise is received by the London, Hall, which is arrived at Brightelmstone from Tobago, that the American Privateers swarm about every Island in order to intercept our homeward-bound Ships, and that many Vessels which have been loaded for some Time are fearful of sailing till they can procure a Convoy to England.

The following letter was received on Saturday from Mr. Charles Barns, Commander of the Snow Blake, in the Service of Government, dated Cadiz Bay, June 20. ー "Yesterday Morning I chased an American Ship, of about 250 Tons, into this Bay, but cannot take her, it being a Foreign Port. I never was more surprised in my Life, when I found there were three American Privateers riding here at single Anchor, and a Number of their Merchant Vessels loading and unloading at their Quays...."