Recovery of Treasure from the wreck of the Thetis. 363 



His Majesty's Ship Thetis." By the Hon. Commander F.T.de Roos, 

 R.N., F.R.S. — was commenced. 



Feb. 27. — The Hon. Commander de Roos's paper was resumed and 

 concluded. 



The author, who had the command of His Majesty's ship Algerine, 

 was instructed to take charge of the enterprise commenced by the 

 officers and crew of His Majesty's ship Lightning, having for its ob- 

 ject the recovery of the treasure and stores from the wreck of the 

 Thetis, which, in the month of December 1830, had sunk in a cove to 

 the south-east of Cape Frio. He reached this spot on the 6th of March, 

 1832, having with him eleven officers and eighty-five men. A certain 

 number of men were appointed to remain on board the ship, which 

 was moored in a harbour two miles off; a party of artificers and others 

 were employed at the huts which they inhabited near the Cape; and 

 the rest, nearly thirty-five in number, were stationed at the wreck. 



The author gives a description of Cape Frio, and of the island of 

 which it forms the south-eastern extremity, which is an immense pro- 

 montory of insulated granite jutting into the Atlantic Ocean, sixty 

 miles east of Rio de Janeiro. The cove, in the middle of which the wreck 

 of the Thetis lay, is a square indenture in the cliffs, six hundred feet 

 deep by as many wide. It is surrounded by nearly perpendicular 

 masses of granite, from one hundred to two hundred feet high, and 

 is exposed to the whole swell of the South Atlantic, which sets in 

 with remarkable force in that direction. The weather is singularly 

 variable ; and transitions frequently take place in the course of a few 

 hours, from perfect stillness to the most tremendous swell. The author 

 states that he has witnessed few scenes in nature more sublime than 

 that presented by the Thetis Cove during a gale of wind from the 

 south-west. 



The author enters into a minute description of the mechanical ap- 

 paratus employed for obtaining the necessary purchases for the various 

 operations which were required, and gives a circumstantial history of 

 his proceedings. Frequent interruptions were experienced from the 

 state of the weather, and the almost incessant agitation of the water, 

 which was often so powerful as to render the diving-bell unmanage- 

 able, and to expose the divers to serious danger. The diving-bell 

 consisted of a one-ton ship's water-tank, with eight inches of iron 

 riveted to the bottom in order to give it. more depth, and having at- 

 tached to it 18 pigs of ballast, the weight of which (17 cwt.) was 

 found to be sufficient to sink it. 



As soon as the necessary arrangements had been completed, the au- 

 thor states that he made a minute survey of the bottom, by means of 

 the diving-bell, and ascertained the exact position and shape of all the 

 large rocks which covered the spot where the treasures and stores of the 

 Thetis had been scattered. The shape of the area where the precious 

 metals in particular had been deposited, was an ellipse, of which the 

 two principal axes measured 48 and 31 feet ; and large boulders of 

 granite had been subsequently rolled over these treasures, and re- 

 quired being removed before the latter cculd be recovered. The su- 

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