DECOMPOSITION OF BORACIC ACID. 



11 



hour's exposure to it, had scarcely diminished in quantity, 

 but the phosphorus had gained a tint of pale green. 



It did not combine with mercury, when they were heated and mercury, 

 together. 



These circumstances are sufficient to show, that the com- Differs from 

 bustible substance obtained from boracic acid by the agency an >' known 

 of potassium is different from any other known species of 

 matter; and it seems, as far as the evidence extends, to be 

 the same as that procured from it by electricity; and the 

 two series of facts seem fully to establish the decomposi- 

 tion, and recomposition of the acid. 



From the large quantity of potassium required to decorn- Boracic acid 

 pose a small quantity of the ucid, it is evident that the bo- contains much 

 vacic acid must contain a considerable proportion of oxigen. ' ^ 

 I have endeavoured to determine the relative weights of the 

 peculiar inflammable matter and oxigen, which compose a 

 given weight of boracic acid; and to this end I made several 

 analytical and synthetical experiments ; I shall give the re- 

 sults of the two, which I consider as most accurate. 



Twenty grains of boracic acid and thirty grains of potas- Apparently in 

 sium, were made to act upon each other by heat in a tube of one li: *tance2 

 brass; the result did not effervesce when washed with dilu-base: ' 

 ted muriatic acid; and there were obtained after the pro- 

 cess, by slight lixiviation in warm water, two grains and 

 about six sixteenths of the olive coloured matter. Now 

 thirty grains of potassium would require about five grains 

 of oxigen, to form thirty-five of potash ; and according to 

 this estimation, boracic acid must consist of about one of 

 the peculiar inflammable substance, to nearly two of oxi- 

 gen. 



A grain of the inflammable substance in very fine pow- in another 

 der, and diffused over a large surface, was set fire to in 

 a retort, containing twelve cubical inches of oxigen; three 

 cubical inches of gas were absorbed, and the black resi- 

 duum, collected after the boracic acid had been dissolved, 

 was found to equal five eighths of a grain. This, by a se- 

 cond combustion, was almost entirely converted into boracic 

 acid, with the absorption of two cubical inches and one 

 eighth more of oxigen. The thermometer in this experi- 

 ment was at 58° Fahrenheit, and the barometer at 30-2. 



Vol. XXIV — Sept. 1809. C Accord- 



