448 Analyses of Books, [June, 



Crsfle in Galloway, of which an account will be found in the 

 Annals of Philusophy, vol. iii. p» 4G5. 



V. An Account of the Brine Springs at Droitwich, By Leonard 

 Horner, F. R.S. M.G.S. — Salt has been made at Droitwich in 

 Worcester for above a thousand years. The structure of the 

 country, as far as it has been ascertained, is this. Uppermost a 

 bed of sand-stone, usually red, but sometimes greenish, and tlien 

 containing veins of gypsum. Mr. Aikin and Mr. Horner consider 

 it as old red sand-stone. Under this lies a bed of gypsum about 

 150 feet thick: below this a river of brine 22 inches deep. Lastly, 

 there lies a bed of rock salt which has never been penetrated. If 

 the sand-stone be old red sand-stone, the position of the gypsum 

 and rock salt is uncommon, as these beds have hitherto been ob- 

 served only above the red sand-stone and never below it. There 

 are four pits at present used at Droitwich, and the quantity of brine 

 which flows out is much greater than can be consumed. The quan- 

 tity of salt manufactured annually is about 16,000 tons. This is 

 chiefly consumed in England, and pays a duty of 320,000Z. The 

 present market price of the salt is 3lZ. per ton, 30^. of which is 

 duty. 



The specifio gravity of the brines of the different pits is as 

 follows : — 



Walker's pit 1-20611 



Walwyn's pit 1-203S3 



Romney's pit 1-20015 



Stuckey's pit 1-1846/ 



Farley's pit 1-17471 



The last pit is not at present in use, and is probably somewhat 

 znixcd with surface water. None of then are perfectly saturated; 

 for water saturated with salt at 55 is of the specific gravity 1-21. 

 Walker's pit ought to contain, by my experiments, 28-8S per cent. 

 of salt ; or three ounces of it hold in solution 470 grains of salt. 

 Mr. Horner, however, obtained by evaporation only 431 86" grains; 

 but it is well known to chemists, that the whole of the salt dis- 

 solved in water cannot be recovered by evaporation. However 

 carefully the evaporation be conducted, a portion of the salt always 

 makes its escape. The quantity of salt obtained by evaporation 

 from four cubic inches of each of the pits, by JNlr. Horner, wa» 

 as follows : — 



Walker's pit 317-14 grains. 



Walwyn's pit 313-40 



Romney's pit 31 1'OO 



Stuckey's pit 283*50 



Farley's pit 266-34 



The salt was dried in the temperature of 180°. The constituents 

 ©f this salt Mr. Horner found as follows : — 



