VOL. LVl.] PHILOSOPHICAL TRANSACTIONS. 341 



go to church in the winter; but there has fallen little snow since the earthquake 

 at Lisbon, and some years none at all. Mr. B. is persuaded it changed the cli- 

 mates of many parts of Spain ; for no man living saw, nor heard his father say 

 he saw, snow fall in or about the city of Sevil, till the year 1756. He found 

 many plants in these mountains which he had seen in Switzerland; they abound 

 with oak, beech, birch, holly, and hazel. The hills and plains are fine pasture; 

 he never saw a meadow in any other part of Spain, neither did he see horses and 

 cows feed on hay any where else. 



These mountains are formed of sand-stone, lime-stone, plaster-stone or gyp- 

 sum, and emery-stone. Tlie sand-stone is at the summit of the mountains, and 

 some hills, and the lime-stone forms the body; but the contrary is seen in others^ 

 the sand-stone abounds, and the plaster is always lowest. As for example, tlie 

 high mountain of Arandilla, which is a small league off the town, is all sand- 

 stone at the summit; its body is a mass of ash-coloured lime-stone, in wiiich ar* 

 found imprisoned petrified cornu amnionis, and scollop shells ; and there are bods 

 of plastfer-stone at its foot, towards the plain; these join to a stratum of black 

 marble veined white and yellow, which is no more than a purer kind of lime- 

 stone, as iill other marbles are. 



On the hill to the east of Reynosa, and in the plain, are found blocks of 

 emery-stone, which the looking-glass grinders of the king's fabric at St. Ikle- 

 fonso say is the most biting emery they ever used; and Mr. B. never saw any 

 other in its native matrix. That iron has been, and is now, in a fluid state 

 percolating through the earth, and that it subsides, crystallizes, or is precipi- 

 tated, to form different bodies, is demonstrated by the black and red blood 

 stone, by some beautiful stalactites, which are almost pure iron, by the eagle- 

 stone, by figured pyrites, by native vitriol, and by native crocus. When this 

 fluid iron penetrates a rock of sand-stone, and only stains the surface of each 

 grain, of a brownish, reddish, or yellow colour, it becomes only sand and 

 crocus; but when it is joined with the crystalline matter in a fluid state, in the 

 very act of crystallization of each grain of sand it incorporates with it, its weight 

 and hardness is increased, and then it becomes emery. 



The earth of the mountains and hills is of the same nature as that of the 

 rock below. If it is lime-stone, the soil cast into any acid liquor will boil up with 

 a violent effervescence, and the acid will dissolve it. If the rock below be sand- 

 stone, or plaster-stone, or emery, the earth of that hill or mountain will remain 

 quiet in the acid, and there is no effervescence nor dissolution. When the 

 rocks below are mixed, calcary and noncalcary, the soil of the surface is also of 

 a mixed nature ; and he always found the action of the acid to be weak or strong 

 on these earths, in proportion to the sort of stone with which they abound. 



Thirty-one leagues south-east of Madrid, and 5 leagues south of the source of 



