14 



DECOMPOSITION OF BORACIC ACID. 



the boracic acid. When this acid had been heated to white- 

 ness, before it was introduced into the tube, and powdered 

 and made use of while yet warm, the quantity of gas given 

 out in the operation did not exceed twice the volume of the 

 acid, and was hidrogen. 

 Large quanti- I could only use twelve or fourteen grains of each of the 



ties could not two su bstances in this naode of conducting the experiment: 

 be used. . » 



for when larger quantities were employed, the glass tube al- 

 ways ran into fusion from the intensity of the heat produced 

 during the action. 

 Effect of naph- When the film of naphtha had not been carefully remov- 

 ed from the potassium, the mass appeared black through- 

 out; but when this had been the case, the colour was ©f a 

 dark olive-brown. 

 Proper propor- I n several experiments, in which I used eqvial parts of the 

 ' acid and metal, 1 found that there was always a great quan- 

 tity of the former in the residuum, and by various trials, I 

 ascertained that twenty grains of the potassium had their 

 inflammability entirely destroyed by about eight grains of 

 boracic acid. 

 Apparatus. For collecting considerable portions of the matters form- 



ed in the process, I used metallic tubes furnished with stop- 

 cocks, and exhausted after being filled with hidrogen. 



When tubes of brass or copper were employed, the heat 

 was only raised to a dull red ; but when iron tubes were 

 used, it was pushed to whiteness. In all cases the acid was 

 decomposed, and the products were scarcely different. 

 Results in a When the result was taken out of a tube of brass or cop- 



copper tube- p el yit appeared as an olive coloured glass, having opaque, 

 dull olive-brown specks diffused through it. 



It gave a very slight effervescence with water, and parti- 

 ally dissolved in hot water, a dark olive coloured powder se- 

 parating from it. 

 In an iron tube. The results from the iron tube, which had been much 

 more strongly heated, were dark olive in some parts, and al- 

 most black in others. They did not effervesce with warm 

 water, but were rapidly acted upon by it, and the particles 

 separated by washing were of a shade of olive, so dark as to 

 appear almost black on white paper. 

 Solutions. rp| ie so i u ^ ons obtained, when passed through a filter, had 



a faint 



