THE STENTOROPHONIC TRUMPET Original: Tuba Stentoro-Phonica. Named after Stentor, the legendary Greek herald in the Iliad whose voice was as powerful as fifty men.

Illustration 1, Figure B.

...of Copper, in the form of an ordinary Trumpet (as is described in Figure B), the length being 16 feet 8 inches, the diameter of the wide end 19 inches, and of the narrow end 2 inches.

I carried this instrument down the river past the Bridge London Bridge, which at the time was crowded with houses and created significant noise from the rushing water below. (accompanied by one or two gentlemen of my acquaintance) as far as a place called Cuckold’s Point A point on the south bank of the Thames in Rotherhithe.. Leaving it there in the hands of a Waterman|A river boatman who ferried passengers across or along the Thames, we rowed down very near Deptford. There, despite the noise of sailors and carpenters in various ships both in front of and behind us, we heard very clearly most words the waterman spoke into it. We judged him to be at least a mile and a half distant from us, and concluded that had the river been free from noise, we might have heard and understood him from much further away.

Illustration 1, Figure C.

After that, I ordered a fourth instrument to be made of copper (as is described in Figure C), about 21 feet in length, the diameter of the wide end being 2 feet, and of the narrow end 2 and ¼ inches. It was of the same figure and shape as the previous one, only it was more precisely crafted.

At the same time, for the sake of variety, I gave directions for a fifth copper instrument. Its length was 5 feet 6 inches, the diameter of the wide end 21 inches, and of the narrow end 2 inches, as seen in Figure D. I also ordered two smaller instruments, each 5 feet 6 inches in length, with the diameter of the wide end being 10 and ½ inches, and the narrow end 1 and ½ inches.
Illustration 1, Figure D. Illustration 1, Figure E.

In one trial, the third and fourth of these instruments were heard from the river opposite Vauxhall all the way to the nearest part of Battersea opposite Chelsea. In another trial, they were heard from Hyde Park Gate to Chelsea College The site where the Royal Hospital Chelsea now stands.. Either of these distances was judged to be over a mile and a half. Based on the trials I have made with the two smallest ones, I believe they could maintain a conversation on a quiet, calm evening at a distance of at least three-quarters of a measured mile.

After this, by His Majesty's King Charles II special command, the three largest of these instruments were sent to Deal Castle. There, several trials were made of them by the Honorable Francis Digby, Esq., Governor of that Castle. A detailed account of this was given in his own hand to the Right Honorable the Lord Arlington Henry Bennet, 1st Earl of Arlington, a leading advisor to the King., His Majesty's Principal Secretary of State, in a letter dated the 14th of October, 1671. His Lordship gave me permission to insert a copy of that letter here.