e 2$S NATIVE SULPHATE OF MAGNESIA* 



XII. 



On the unerpefted Produclion of Sulphate of Magncfia. By 

 J. Bostock, M. D. 



To Mr. NICHOLSON. 

 SIR, 



Liverpool, Nov. 18, 1802. 



1 FEEL fomewhat doubtful whether the fiibjecl of the fol- 

 lowing communication*may appear to you Sufficiently intereft- 

 ing, or the experiments detailed with a fufficient cfegree of ac- 

 curacy, to entitle it to a place in your Journal. I have how- 

 ever fent it for your infpeclion ; if you think it of any value, 

 it is completely at your fervice. 



I remain, 

 your's, &c. 



JOHN BOSTOCK. 



Copious faline ABOUT two years ago, a houfe was erecled in the neigh- 



tSTnner n f«r- n bourhood of this town b y Tho « Earle > Efc l- u P on his e ^ ate of 

 face of a brick Brook Farm. The walls, which were chiefly conftru&ed of 

 waI ** ftonc, were lined with bricks, formed of clay procured from 



the foundation. Some months after the erection of the build- 

 ing, a large part of the bricks were covered with an extremely 

 copious, faline efflorefcence. Mr. Earle felt anxious left this 

 peculiar fubftance mould prove injurious to the plaifter, with 

 which it was propofed to cover the walls, and was defirous 

 to be informed respecting its nature. With this intention th© 

 following experiments were performed. 

 Analytic experi-' The fait was diflblved in water, filtered, and gently evapo- 



snents to deter- rated lt cry ft a llj ze d with difficulty, and the cryftals were too 

 mine its nature. 7 . J . JW , J 



indeterminate to atcertain precilely their figure. The lalt thus 



purified had a bitter, acrid tafte ; it neither efflorefced nor 

 deliquefced after being expofed for feveral months to the at- 

 mosphere. It was very foluble in water ; 100 grains of water 

 at the temperature of 55°, diflblved nearly 50 grains of the 

 fait ; and the fame weight of water at the boiling heat, dif* 

 Solved nearly three times that quantity. 



I. to 



