KARSTEN ON THE ROCK-SALT DEPOSIT AT STASSFURTH. 13 
Even in the first 60 feet of depth, salt water with 7:9 per cent. 
saline matter (Rohsalz) was found, which rose to within 18 feet of 
the surface. At 550 feet depth in the sandstone, the salts had in- 
creased to 12°7 per cent., and rose rapidly to 18°3 per cent. in the 
soft white gypsum, and in the anhydrite beds to 21°8 per cent. Un- 
fortunately these salts were not compared chemically with those of 
the neighbouring salt spring, which contain only 5°507 per cent. of 
impure salts, and consequently 94°493 of pure chloride of sodium. 
This is especially to be regretted, because in the firm compact an- 
hydrite at 776 feet 9 inches the saline matter suddenly rose to 27401 
per cent., or nearly to saturation. 
The joy at the discovery of this rich salt spring, whose specific 
gravity and consequently saline contents further imcreased in the rock- 
salt, was however disturbed by the discovery that in the 31°1 per 
cent. of sale matter it then contained, there was only 15°815 per 
cent. of common salt, and consequently more than a half was foreign 
salts, of which 12°99 per cent. was chloride of magnesium. This 
well therefore contained less common salt than even the neighbour- 
ing spring with only 1°13 of specific gravity. This unexpected 
event caused the investigation of the rock-salt first bored through, 
when it appeared that it consisted of common salt and epsomite 
(Bittersalz) in very variable proportions, they bemg probably altered 
and partially dissolved by the water of the spring before reaching the 
surface. Only once some fragments of the rock-salt were obtained 
apparently in an unaltered condition. Analysis showed the very 
eculiar composition of this salt, in which 10 atoms of common salt 
(chloride of sodium) were combined with 1 atom anhydrous epsomite 
(sulphate of magnesia), so that the Martinsite consists of 90-73 of 
the former and 9°27 of the latter ; three analyses having given 90°98 
and 9°02 respectively, not taking into account 0°3 per cent. of 
matter insoluble in water, which was at first supposed to be gypsum, 
but on further investigation found to be chiefly boracite. The Mar- 
tinsite yields a bitumimous odour when rubbed, and crackles when 
dissolved in water, like the decrepitating salt of Wieliczka. 
As the boring proceeded in the rock-salt, the saline matter, con- 
trary to expectation, became more impure, the water not only con- 
taining a larger proportion of epsomite, but also of earthy matter in- 
soluble in water. The water from the depth of 963 feet yielded 
33°28 per cent. of saline matter; but in this there was only 7°15 
per cent. of common salt, the essential constituents being epsomite 
and chloride of magnesium. The water was also very impure with 
gypsum and other substances. In the salts obtained by evaporation 
hydrous peroxide of iron occurs, which seems to exist in the water, 
not as the protoxide combined with carbonic acid, but as a muriate of 
the protoxide of iron, as the clear water, after remaining long ex- 
posed to the air, deposits a basal muriate of the peroxide of iron. The 
great diversity in the nature of the salts in this well and in the 
original spring only 170 feet distant, is however very difficult of ex- 
planation. 
Great quantities of debris falling iato the bore from the bed 
