[ 44 ] [Book VI. 



C H A P. VIII. 



COMBINATIONS OF THE OTHER MINERAL ACIDS. 



Sparry Tartar. -Sparry Soda. Borax ; its Properties ; its U/e in the 

 Arts. Combinations of neutral Salts -ivit/j Metals. 



THE combinations of the other mineral acids 

 with the alkalies, have in general been very im- 

 perfectly examined, and I fhall therefore be very brief 

 in treating of them. 



The SPARRY TARTAR, or fltiat of pot-afh of the 

 French chemifls, is compofed of the acid of fpar united 

 to the vegetable alkali. It is always in a gelatinous 

 form, and has fo ftrong an attraction for water, that it 

 cannot be cryftallized. According to Scheele, it is 

 acrid, cauilic, and deliquefcent, when dried and melt- 

 ed ; he compares it in this irate to the liquor of flints. 

 It appears, that the fire difengages the fparry acid, and 

 that the filiceous earth taken up by the acid melts inro 

 a foluble earth by means of the fixed alkali. This fait 

 has not been applied to any ufe. Of the fparry foda 

 Hill lefs is -known j and the fame may be affirmed of 

 the fparry ammoniac. 



The combinations of the acid of borax have not 

 attracted much more attention, except the fubftance 

 from which this acid derives its name. BORAX, the 

 bora^ of foda of M. Lavoifier, is compofed of a pe- 

 culiar acid united to the mineral alkali. The form 

 in which it is expofed to fale is that of cryftals, very 

 tranfparent, and containing a large proportion of water. 

 When a fmall quantity of borax is heated fo as to 

 diffolve in its own water, it boils in a white foam; 

 and when the water is diffipated, the fait is found to 



have 



