%6o ESSAYS AND OBSERVATIONS 



fimilar to that obtained from the brine of 

 falt-petre, was hkewife produced by the 

 evaporation of thofe waters which contain 

 common fait, had the curiofity to try if this 

 would alfo yield a mag?iefia. The experi- 

 ment fucceeded : and he thus found out 

 another procefs for obtaining this powder, 

 and at the fame time affured himfelf by ex- 

 periments, that the produdt from both was 

 exadly the fame *. 



My curiofity led me fome time ago to in- 

 quire more particularly into the nature of 

 magnefia^ and efpecially to compare its pro- 

 perties with thofe of the other abforbent 

 earths, of which there plainly appeared to me 

 to be very different kinds, altho' commonly 

 confounded together under one name. t 

 was indeed led to this examination of the 

 abforbent earths, partly by the hope of dif- 

 covering a new fort of hme and lime-water, 

 which might poffibly be a more powerful 

 folvent of the ftone than that commonly 

 ufed J but was difappointed in my expeda- 

 tions. 



I have had no opportunity of feeing Hoff- 

 mann firfl magnefia or the liquor from which 



it 



* Hoff. Op. T. iv. p. 500. 



