g(> ANALYSIS BY BORACIC AClt>. 



of the flieoi^ of edly celebrated philofopher, are intitled to rights whtcli will 

 combuftion. prreatly modify the iinqflalified claim he has made. 1 cannot 

 now fay, vvhellier Rey did, or did not make experiments, but 

 whether he did or not, he certainly inuft have founded his 

 nilr»)dticlions upon fa6ts ; and between llie nbfervation of well 

 eftabliflied faiSs, and the making of direct experiments there 

 feems lo be no eflenfial dilTerence. How it has happened that 

 t!ic great Robert Hooke, who had invelHgated the modern 

 tbeory of combuftion in IS64 and pjbliflied it in an ample de- 

 fail on his micrographia in 1673*, and John Mayow, who 

 foon afierwards, or about the fame time edabliflied the fame 

 do^^rine, and extended it to phyfiological refults, are over- 

 looked by our author, appears to require fuir.e difciiffion. I 

 (liall take an early opportunity of leluming this fubject. 



XIX. 



On a Method of analyzing Stmies containing fixed Alkali, hy 

 j\Ieamoft1i€ Borncic Acid.' By Huinphri/ Daiy, Efq. /^, R. S. 

 Profeffbr of Cheviifiry in the Uoycil Injlitutidnf. 



Ai-id cf borax 

 »pry iifefal in 



it combines 

 with earths by 

 ignitiop and 

 quits them to 

 mineral acids. 



Procefl'es. 

 Pulverize the 

 Rone and faft 

 with two parts 

 feoracic acid. 

 Dijcft with 

 weak nitric acid, 



Evaporate* 



1 HAVE found the boracic acid a very iifeful fubftance for 

 bringing the conftituent parts of ftones containing a fixed alkali 

 into iblution. 



Its attraction for the different fimple earths is confiderable at 

 the heat of ignition, but the compounds that it forms with 

 them are eafily decompofed by the mineral acids diflblved in 

 water, and it is on this circumnance that the method of analyfis 

 is founded. 



The procefies are very fimple. 



100 grains of thcftone to be examined h very fine powder, 

 mufl be fufed for about half an hour, at a firong red heat, in 

 a crucible of platina or filver, with 200 grains of boracic acid. 



An ounce and half of nitric acid, diluted with feven or eight 

 times its quantity of water, mufl be digefied upon the fufed 

 mafs till the whole is decompofed. 



The fl.uid muft be evaporated till its quantity is reduced to 

 an ounce and half or two ounces. 



Copied In our Journal quarto feries III. 479. 

 t Phil. Tranf. Part II. for 1805. 



If 



