270 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. 



his arrival in town; and he continued well, taking daily, as he had constantly 

 done from the time he went last into the country, the full quantity of soap and 

 lime-water, as formerly he took. 



LXXVIII. Part of a Letter from Mr. John Parker, an English Painter at 

 Rome, to his Father at London, concerning the late Eruption of Mount F^esu- 

 vius. Dated Rome, Dec. 20, 1751. p. 474. 



The eruption lasted about 25 days in all, and broke out of the side of the 

 mountain, preceded by an earthquake, felt all over Naples at the time of the 

 eruption. The mountain in the middle of the crater or cup, which formerly 

 threw out the stones, sunk down, with about a third of the bottom of the said 

 cup. The breadth of the matter it threw out is in some places half a mile over, 

 in the least part near 6o feet; and it has filled a valley about 6o feet deep, and 

 raised a mountain in the same place, of matter and ashes, about 50 feet high; 

 and its whole length from the mouth to where it stopped, is about 5 miles; but 

 it did not arrive at the sea by near 5 miles. The matter, or lava, seems to be 

 composed of iron, antimony, sulphur, and salts, and is not always of the same 

 colour, taste, &c. in every place. The thing I can compare it to most, is the 

 large cinders thrown out of your great iron works, but covered over in many 

 places with the above salts and sulphur. While the lava ran red-hot, a man 

 threw a mass of the cool lava from a height upon it, which, far from sinking 

 into it, rebounded like a ball. Its motion was as slow as the common walk of a 

 man. It broke out in 5 different places. Mr. P. walked on it for about a mile 

 while near 3 feet of the top were cooled; but for many feet underneath as red to 

 the sight as the furnace of a glass-house. It covered and burnt up trees, houses, 

 &c. in short all it found in its way. 



LXXIX. The Case of a Piece of Bone, with a Stone in the Bladder, success- 

 fully extracted, by Mr. Joseph Warner, F.R.S. and Surgeon to Guy's Hos- 

 pital, p. 475. 



Eliz. England, aged 48, in all other respects a healthy woman, had been 

 afflicted with the symptoms of the stone in the bladder for about 2 years. After 

 the usual preparation Mr. W. proceeded to the operation in the following un- 

 usual manner: He cut the urethra obliquely upwards on the right side, to about 

 half its length, by introducing a small knife into the groove of the staff, and 

 found very little force requisite to the introduction of the necessary instruments 

 into the bladder, and in the extraction of the stone, &c. On laying hold of the 

 stone it broke; so that only a part of it, about the size of a pigeon's egg, was 

 extracted on the first introduction of the forceps; but at the second time, he 

 extracted a ragged piece of bone, weighing l6gr. Before it was cleansed, its 



