1810. | 
appeared almost black. It was permanent 
in water, butsoluble with effervescence in 
warm nitrous acid. When heated to 
redness upon the platina it burnt slowly, 
and gave off white fumes, which slightly 
reddened moistened litmus- paper, and it 
lefta black moss, which, when examined 
by the magnifier, appeared vitreous at the 
surface, and evidently contained a fixed 
acid. In another experiment the boracic 
acid, heated in contact with potassium 
in a gold tube, was converted into borate 
of potash, at the same time that a dark- 
coloured matier, similar to that produced 
“by electricity, was formed. Thus the 
evidence for the decomposition of the 
boracic acid ig easily obtained, hut ‘the 
Synthetical proofs of its nature involve 
more complicated circumstances. Mr, 
Davy found that, when equal weights of | 
potassium and boracic acid were heated 
together, there was a most intense igui- 
‘tion before the temperature was nearly 
Taised to the red heat; the potassium en- 
‘tered into vivid inflammation when it 
‘was in contact with the boracic acid. 
When this acid had been heated to white- 
ness, before it was introduced into the 
‘tube, and powdered and used while yet 
“warm, the quantity of gas given out in the 
operation did not exceed twice the vo- 
ame of the Acid, and was hydrogen, Ye 
“only used twelve or fourteen grains of 
each of the two substances in this mode 
‘of conducting the experiment; for when 
larger quantities were employed, the glass 
‘tube always rah into fusion from the in- 
tensity of the heat produced daring the. 
action. Tn mauy experiments in which 
hé used equal parts of the acid and metal, 
Ne found’ that there was always a great 
quantity of the former in the residuum; 
and by various trials he ascertained that 
twenty grains of potassium tad their in- 
flammability entirely destroyed by about 
eight grains of boracic acid. Forcollect- 
ing considerable portions of the matters 
‘formed in the process, he used metallic 
tubes furnished with stop-cocks, and ex- 
hausted after having been filled with hy- 
drogen. When tubes of brass or copper 
were employed, the heat was only raised 
to a dul! red; but when iron tubes wore 
used, it was pushed to whiteness, In all 
cases the acid was decompused, and the 
prodacts were scarcely different. When 
the result was taken out of a tube of 
brass ur copper, it appeared as an olive- 
coloured mass, having opaque dail olive- 
brown specks diffused through it: in 
this, way he ccllected the largest quanti- 
ties. It appears asa pulverulent mass of 
Monraty Mac, No. 200. 
Proceedings of Learned Societies. 
385 
the darkest shades of olive; is perfectly 
opaque; very friable ; and its powder does: 
not scratch glass, “It's a non-conductor 
of electricity. It ‘gives off moisture by. 
ingrease of temperature, and if heated in 
the atmosphere takes fire at a tempera- 
ture below the boiling point of oil, and 
burns with a red lieht, and seintillations 
ike ‘charcoal, The phenomena of its 
combustion are best witnessed in a 
retort filled with oxygen gas. When 
the bottom of the retort is gently 
heated by a spirit lamp, it throws off 
most vivid scintillations, like those from 
the combustion of the bark of charcoal, 
and the mass burns with a brilliant light. 
A sublimate rises from it whichis Bora. 
‘cic acid.” In oxymufiatic acid gas, the | 
“peculiar inflammable substance occasi- 
ons some beautifel phenomeiia; when 
brought in contact with the gas it ins 
stantly takes fire and burns with a bril- 
Jiant white light, a white substance coats 
the interior Of the vessel, and the sub- 
Stance i{self is found covered by a white 
film, which, by washing, affords boracic | 
acid, and leaves a black matter behinds « 
The properties of this matter are enus 
merated; ‘and the inference drawn is, 
that it is different from any other known 
Species of matter, and is the saine as that 
procured from it by electricity : thus is 
established the decomposition and reconia 
position ofthe acid. From other expé.. 
riments it would seem that boracic acid 
consists of one part of inflammable mats 
ter and 1:8 of oxygen, and the dark re- 
sidual substance, supposing it to be sim 
ply the inflammable, matter combined 
with less oxygen than is sufficient to cons 
stitute boracic acid, would be an oxide 
consisting of about 4°7 of inflammable 
matter to 1°55 of oxygen, Mr, D. hike- 
wise thinks that the combustible matter 
obtained from boracie acid, bears the 
same relation to that substance as-sul- 
phur and phosphorus do to the sulphuric 
and phosphoric acidsg bur it is still a 
question whether it is an ‘elementary 
body, .the pure basis of the acid? or 
whether, hke sulphtr and phosphorus, 
‘it is compounded? © There aremany cir- 
‘cumstances which *tavor the idea that 
the dark olive substance is not 4 simple 
hody ; its being non-conducting, its change 
of colour by being ‘heated in hydrogen 
gas, andits power of combining with al- 
kalies ; for these properties, in general, 
belong to primary compeunds that are 
known to contain oxygen. Some of ‘this, 
olive inammable matter he treated in a | 
different way, and the result led Mr. D. 
f 4F to 
