On tht Dectmpofition of the Acid of Borax. 259^ 



modem chetnifts ; which has taught us, that difRcuh decompofitions of parts clofely united, 

 are more eafily efFeclcd by a gentle long-continued digeftive heat, and repeated diftillation 

 of the fame menftruum, than by a heat which is more violent, and operates more quickly. 



I firft made fonie preliminary experiments, in order to judge what probability there might 

 beoffuccefs. 



Experiment J. I poured an ounce and a half of the abovemeiitioned acid upon two drams 

 of fedative {^^It in a retort, to which I adapted a proper receiver, and then placed the mixture- 

 in a gentle digeftive heat of from 143° to 200° of Fahrenheit. The fluid was dillilled over 

 very flowly, and the fait was dry on the third day. The fait in the retort feemed unchanged; 

 nor had the marine acid loft any thing of its ufual fmeil. 



Exbcr. II. I poured the diftilled fluid cut of the receiver upon the fame fait, and expofed 

 tliem to the fame degres of heat as b^ifore. The fait again became dry on the third day, but 

 there was yet no appearance of any change. 



Exper. III. I repeated the fameprocefs a third time. I now perceived, during the diflillatory 

 digeftion, feveral bright yellow fpots upon the fait as it afcended the fides of the retort, re-- 

 fcmbling weil-formed ammoniacal flowers of iron ; more of which I difcovered after the 

 entire exhalation of the fluid. 



Exper. IV. The above change induced me to repeat the diftillation ; and I then perceivedj 

 not only as many, but a much greater number of bright y:llow fpois, fome of which were 

 even much darker in colour, and approaching to brown. A change had now evidently taken 

 place, which change encreafed up n every rep. tiiion of the procefs ; I therefore judged I- 

 might follow this indication with confidcn:e. But with a view to ufe the greateft accuracy 

 and precaution in my proceedings and obfcrvations, 1 rcfolved to begin my work over again. 



Firft, I procured fome ounces of fedative f.ilt, which had been obtained from borax by 

 means of vitriolic acid, and tiien prepared two quarts of the abovementioned oxygenated mu- 

 riatic acid, by diftiliing three parts of muriatic acid with one ).art of the pureft manganefe in 

 the ufual manner; this I pref^rved in a cool dark place. Thus the fubftances ufed'in the 

 following experiments were always of the fame nature. 



Exper. V . I poured three ounces of the oxygenated muriatic acid upon half an ounce of 

 the fedative fait in a white glafs tubulated retort. I ufed fuch a retort that (infrequently 

 pouring back the diflilled fluid) I might not have to lute afreih the feveral velTels after every 

 diftillatory digeftion. For the fame reafon alfo I chofe a tubuLited receiver, the tube of 

 which gradually terminated in a point in fhap. of a funnel. This tube paffed into 

 a phial placed in fuch a manner, that all the fluid pafling into the receiver dropped im- 

 mediately into the phial,, the jomings of which were cloftd with bladder. To clofe ths 

 tube of the retort I did not think it right to ufe a waxed cork (though it clofes very tight), 

 becaufe it might be corroded, and alfo becaule the vapours dropping from the cork might 

 carry fome fat and oily matter back into the retort. For th>; fame realon I would not ufe 

 any greafy lute; butclofed the joints of the glafs ftopper (which fitted remarkaoly clofe) with 

 a ring of tine fealing-wax, clofely preffed upon it, but which could be eafily difengaged after 



ray 



