19)5.] Scientific Intelligence. 471 
the jar.. Atmospheric air being again admitted into the receiver, 
the mercury entered into the jar, and the elastic fluid condensed 
into a liquid.on its surface. This liquid was chloro-cyanic acid. It 
possessed the following properties. 
“(It is colourless. Its smell is very strong, exciting tears, It 
reddens litmus, is not inflammable, and does not detonate when 
mixed with twice its bulk of oxygen or hydrogen gas. _ The specific 
gravity of its vapour is 2-111, Its solution in water does not pre- 
cipitate nitrate of silver nor barytes water. The alkalies absorb it 
completely. When an acid is poured into this solution the chloro- 
cyanic acid is decomposed, and converted into muriatic acid, car- 
bonic acid, and ammonia. ‘This acid being composed of a volume 
of chlorine united to a volume of cyanogen, without any diminution 
of bulk, is analogous to muriatic acid, hydriodic acid, and dydro- 
cyanic acid, only the chlorine performs the part of the hydrogen 
which constitutes the acidifying principle in these last acids. 
IX. Dr., Murray, of Edinburgh's, Method of preventing Explo- 
; sions in Coal-Mines from Fire-Damp. . 
At the second meeting of the Royal Society of Edinburgh for 
the winter session, a paper was read, by Dr. Murray, on a plan for 
lighting mines so as to guard against explosions from the kindling of 
fire-damp. It had been before explained to several scientific Gen- 
tlemen, and announced in the public papers; and an outline of it 
had been transmitted to Newcastle, where a very favourable opinion 
had been expressed with regard to it. The leading idea on which 
it is founded is, that the inflammable gas constituting fire-damp 
accumulates in the roof of the passages and workings of the mine, 
mingling with the atmospheric air, and at length forming a mixture, 
which is exploded by coming in contact with the candles or lamps 
of the miners; and that this mixture can never accumulate so as to 
fill the whole space, at least while the mine is worked, for the miner 
would become affected by breathing the carbureted hydrogen gas, 
jndependent of other appearances which would indicate its pre- 
sence.’ ‘The simple means of security, therefore, against its explo- 
sion, is to bring the air to sustain the flame of the lamp or candle 
from the floor of the mine; and this is easily done, by burning the 
lamp within a glass case, having a small aperture at the top to 
admit of the escape of the heated air and smoke, of such a size that 
the current shall always pass outwards, and thus prevent any of the 
external air from entering by it, and having attached to the under 
part of it a tube reaching to the floor of the mine to convey the air 
to the flame. In the fixed lamps this tube may be of iron or 
copper; and moveable lamps, which the miner can carry in the 
hand, may be constructed with a flexible tube of prepared leather, 
varnished, of such a length as to reach to the floor. . . 
Besides the security given by this apparatus by bringing the air 
_ to support the flame from the floor of the mine, it has other means 
of security ; one in particular, Dr. M. remarked, is the rarefaction 
ef the air within the case ; whence, if even any mixture of inflam- 
