Boston, Sept. 28. By Letters from Newport on Rhode-Island we have the following Particulars, concerning the tragical Affair, which, for a few Days past, has been Matter of much Speculation among us, viz. That the Sloop Dolphin, Burthen about 20 Tons, of which Adam Duchefeau was late Commander, bound from Cape Francois to Rhode-Island, arriv'd at Block-Island on the Lord's Day the 17th Instant. His Mate and Boy, had been barbarously murder'd on their Passage, in the following Manner: On the 2d Instant, when they were in the Latitude of about 27 and 28, they had a hard Gale of Wind, a Lad being then at the Helm, was not able to steer, by Reason of the Seas running so high, whereupon the Captain order'd a Frenchman to come and take the Helm, but he being in a sullen Humour, made no better Steerage than the Boy; upon which the Captain gave him a Blow, and call'd to an English Passenger named Merchant, to come and steer, which he comply'd with accordingly; the Captain then being on the Quarter-Deck striking Fire to light his Pipe, the Boatswain, who was a Frenchman, nam'd Peter Legrand, took up a Broad Axe, and with one Stroke split his Brains out. The Mate seeing the Captain thus inhumanly butcher'd, ran upon the Quarter-Deck to know the Reason, but there met with the same Fate, and both their Bodies were thrown over-board by the said Legrand and two other Frenchmen of the Company. The Englishman at the Helm being in a great Consternation at what had happen'd, let it go, expecting to be kill'd next: but the said Legrand came to him, and order'd him to take hold of the Helm again; and steer as he should do, or else he should be serv'd as the others had been: upon which he took the Helm again, and was spared. When they came to Anchor off Block-Island, the said Legrand, conscious of what he had done, and fearing a Discovery thereof, by the two English Passengers and a Boy on board, went into the Cabin and loaded two Pistols, and then came upon Deck, with one of the Frenchmen, and commanded the said two English Passengers to throw over-board the said Boy; whose Name was Stephen Decheleau, Nephew of the above said Capt. Decheleau, and if they refus'd, they would shoot them immediately; whereupon the said two Passengers, thro' Fear of being kill'd, consented, and threw the said Boy over-board, who was drown'd. We are also inform'd, that the next Day after their Arrival at Block-Island, as they were coming to sail for a more convenient Place to Anchor in for a few Days, the Sloop miss'd Stays, and driving on the Rocks was bilg'd, which 'tis thought was done by the Means of the two English Passengers, in order to discover this horrid Scene of Iniquity, and bring the Offenders to Justice; for the Sloop having met with this Disaster, the People on Shore readily went off to help them, which gave the Englishmen an Opportunity of discovering the whole Affair: Whereupon they were all apprehended and brought to Newport the next Day, where having been examin'd, they were committed to Gaol, and the Frenchmen laid in Irons. The Persons Names which belong to the aforesaid Sloop, who are secur'd in Gaol as beforementioned in order for Trial, are Peter Legrand, Peter Jaeau, Francis Bowdoin and John Coaprey; and the two English Passengers, Thomas Davis of Newport, and John Merchant of Martha's Vineyard. We also hear that the chief of their Cargo is Molasses and Brandy, with some Chests of Wine, and that most of it is like to be sav'd, which the Authority has sent proper Persons to secure and take Care of 'til further Orders.