704 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. 



sides. They are from 3 to 8 sides, and of all the intermediate numbers. The 

 length of the prisms is unequal, from 2 to 5 feet long. The thickness of them 

 is not at all more equal : it is of 9 inches and under. Many of them form a 

 pillar by lying one upon another; all their ends and joints plain. The pillars, 

 formed by several of those stones, are placed exactly one against the other, with- 

 out having any void between them. They are in a situation almost perpendi- 

 cular. On breaking these stones, their colour appears clearly to be black. It is 

 a kind of pretty hard basaltes. It strikes fire with steel ; and it appears to be very 

 like that of the Giants Causey in Ireland. 



This stone must be very common in the country of Nassau. At some leagues 

 distant from Weilbourg, is an old castle almost entirely built of it. In going 

 from Weilbourg to Coblentz in the electorate of Treves, he observed on the 

 road thither, in the towns and villages through which he passed, that this ba- 

 saltes was made use of in the buildings and pavements. He made the same re- 

 mark in his journey from Coblentz to Cologn through Bonne. He found a 

 pretty large heap of it in a village 3 leagues from Bonne. In continuing his 

 journey along the Rhine, in his way to Bonne, he saw in the river, the waters 

 being pretty low, a rock, which stood a foot or two out of the water, which was 

 a mass of those prisms of basaltes, the heads of which appeared ; and which he 

 concluded was the top of a natural mass of the stone. Hence he was convinced 

 that there were quarries of it along the Rhine. In coming near Bonne, the 

 parapet-walls along both sides of the high road, are found built of these basaltes 

 stones. There are many of them in the old walls of the ramparts of Bonne and 

 Cologn, and in the pavements of those cities. Some authors mention quarries 

 of this basaltes in Upper and Lower Saxony, and in Silesia. 



Those who have made observations on salts, and inquiries into stones, mine- 

 rals, and metals, know how common crystallizations are in nature. A very 

 great variety are found in searching mountains, visiting caverns, and descending 

 into mines. There are few of the naturalists, accustomed to these researches, 

 who shall observe the basaltes above mentioned, but will be inclined to consider 

 them as so many crystallizations. 



LXXXFIII. Account of a Work published in Ilalian by Fitaliano Donati, M.D. 

 containing, An Essay towards a Natural History of the Adriatic Sea. By Mr. 

 Abraham Trembley, F.R.S. From the French, p. 585. 



In this work. Dr. Donati examines both the earth and the sea, and even the 

 soil under the sea, to discover their fossils and other productions. His inquiries 

 have enabled him to determine, that there is very little difference between the 

 bottom of the Adriatic sea and the surface of the neighbouring countries. There 

 are at the bottom of the water, mountains, plains, vallies, and caverns, just as 

 on the land. The soil consists of different strata placed one upon another ; and 



