on the Salt Mines at Car dona. 327 



purity; and in order to be converted into snow white culinary 

 salt requires no other process but grinding. The greyisli hue of 

 the external surface is owing to the rain penetrating a portion of 

 tlie salt, and by diminishing its opacity, depriving it of the white- 

 ness which the fresh fracture generally presents. At the period 

 of my visit the surface of this immense mass was perfectly dry, 

 and in some places, where water had most recently flowed, was 

 covered with a snow-wliite efflorescence. This circumstance, 

 as well as the sharpness of the e;lges above mentioned, show the 

 little hygroinetric water in the atmosphere of that country, and 

 the general purity of the salt from earthy muriates. 



The fracture of the salt is highly crystalline, and usually ex- 

 hibits large granular distinct concretions, vvliich give it some- 

 times the appearance of a breccia, or of containing imbedded 

 crystals. 



A perennial brine spring flows at the foot of the great preci- 

 pice, and affords a strong ]noof of the little eifect of water on 

 this very compact salt. The aperture through which the stream 

 has issued for manv vears, is not wider esternally than two feet, 

 and suddenly contracts to a ^nw inches ; while the channel worn 

 in a solid floor of salt, through v/hich the stream has long flowed, 

 is not a foot in depth. This is partly to be ascribed to the water 

 being saturated with salt; but during the rainy season the 

 stream is much augmented, and thus cannot be supposed so 

 highly charged with saline matter. Notwithstanding this, neither 

 the solvent nor mechanical effects of the spring seem to have 

 much effect on the fossil salt of Cardona. The waters of this 

 spring flow iuto the Cardonero, leaving in the valley a thick 

 scaly crust of salt, resembling the ice formed around our brooks 

 in similar situations. During the rainy season, it is asserted 

 that tile stream carries down such cpiantities of salt into the 

 Cardonero as to kill the fish in that river. This assertion rests 

 upon the autliority of Bowles, an able naturalist ; but he un- 

 doubtedly was led into error when he asserted, that the waters 

 of the Cardonero at some leagues below the mines yield no 

 trace of salt: from which he inferred, that salt may, hj motion, 

 be converted into earthy matter. At Manresa, which is about 

 twenty miles below Cardona, I tested tlie water of the Cardonero 

 by nitrate of silver, which indicated the presence of an unusually 

 kirge portion of muriate of soda. The taste of the l)rine s|)ring 

 at Cardona is intensclv saline ; and the hand immersed in it, on 

 being exposed to the air, is instantly covered with a film of salt. 

 The salt rock near its source is most elegautlv veined with deli- 

 cat© waved delineations of an ochre yellow colour. 



The clay which covers the bed of salt at Cardona and forms 

 the hides of the valley, exactly resembles the clay found iu the 



"X 4 salt 



