ON THE SALT SPRINGS OF M'ORCESTERSHIRE. 375 



Where native brine is obtained, the supply of it is generally 

 in great abundance. The Droitwich springs are so powerful 

 as to raise the brine to the surface, and it overflows when not 

 reduced by pumping. At Stoke Prior the supply is also abun- 

 dant, but the level of the surface being much higher, the brine 

 does not reach nearer to this than twenty yards. The brine at 

 Droitwich is met with at the depth of 170 feet, while at Stoke 

 Prior the depth is 330 feet. It is a remarkable fact that the 

 difference in the surface levels of the two situations is just about 

 equal to the difference of depths ; shewing, that although the 

 two places are nearly four miles distant from each other, the first 

 bed of rock-salt is perhaps exactly at the same level. 



Native brine, as it springs up from the earth, is beautifully 

 transparent. Being derived from so great a depth it is not 

 subject to those variations of heat which affect more shallow 

 springs, the temperature observed being generally 62 degrees. 

 The specific gravity at the Droitwich spring varies from 1.190 

 to 1.200 : that furnished by the spring at the works of Mr. A. 

 Reid, at Stoke Prior, has a gravity of 1.150; and the brine 

 obtained from the spring of Messrs. Fardon and Gossage, at 

 the latter place, possesses a specific gravity of 1.207, being 

 fully saturated with salt. Perfectly saturated brine contains 

 26 per cent, of pure salt, and about a quarter per cent, of 

 sulphate of lime. An imperial gallon weighs 12.07 pounds 

 avoirdupois and contains 3.13 pounds of salt. The brine springs 

 of Cheshire range in specific gravity from 1.150 to 1.200, and 

 in their contents of salt from 20 to 26 per cent. Sea water con- 

 tains rather more than two per cent, of common salt. Iodine 

 and bromine have been discovered to exist in the salt springs of 

 Cheshire, and in many other natural springs by Dr. Daubeny, 

 but I have not been able to discover either of these powerful 

 agents in the Worcestershire brine. In order to confirm or 

 refute my own observations, I sent a portion of brine to my 

 friend. Dr. Thomson, of Stratford, whose abilities as an accom- 

 plished chemist are well known, and he informs me that 

 his analysis failed to detect either iodine or bromine in the 

 brine. In procuring the salt from brine, the temperature 

 required for boiling the solution is equal to 229 degrees 

 of Fahrenheit's thermometer. This process yields what is 

 usually called fine salt, the same that is employed for domestic 

 purposes. Another kind, called broad salt, is made by evapo- 

 ration at a lower temperature, by which the crystals being 

 formed more slowly, and in a fluid not agitated by boiling, be- 

 come more perfect in their form and of a greater size. This 

 kind of salt is chiefly exported, and employed for curing pro- 

 visions. When the process of evaporation is conducted still 

 more slowly, very large crystals are obtained, which are sold 

 under the name of British bay salt. During the making of fine 



July, 1835. — VOL. II. NO. xii. 3 c 



