SCIENTIFIC SUMMARY. 
207 
in the fusing mass indicated a constant temperature of 45° F. In small 
quantities the crystals rapidly fuse when the bottle containing them is 
placed in warm water. The original glycerine was pale brown ; the crystals 
formed from it are nearly white, whilst the liquid which drains away from 
it is dark brown. In quantity, the solid glycerine looks very like a mass of 
sugar candy. The isolated crystals are sometimes as large as a small pea ; 
they are brilliant, and highly refracting j when rubbed between the fingers 
they are very hard, and they grate between the teeth. Their form appears 
to he octahedral, hut this is difficult to ascertain accurately, owing to the 
viscidity of the mother liquor which adheres to them.” The specimen 
examined was first discovered by Dr. W. S. Squire, of the firm of Burgoyne, 
Burbidges, and Squire, of Coleman Street. 
The Absorption of Hydrogen and Carbonic Acid by Melted Copper . — M. 
Caron has presented to the French Academy a memoir on this subject. The 
following is the account given of the mode of experimentation : — Copper of 
good quality, weighing about 200 grains, is melted in a vessel placed in a 
porcelain tube, and by degrees is passed over it a stream of hydrogen, the 
apparatus being so arranged that the copper could be seen during the whole 
operation. As soon as the metal fused it appeared to intumesce, and water 
was condensed on the cool part of the apparatus. When the oxide which the 
copper contains is completely reduced, the surface of the metal is as brilliant 
and mobile as that of mercury. On cooling, a little before solidification, 
the mirror-like surface becomes agitated and appears to boil up, the escaping 
gas projecting a multitude of fine drops of copper. The metal then swells, 
and the solidification terminates by a final incomplete eruption. The ingot 
of metal, after cooling, is found to be porous. Exactly the same phenomenon 
takes place when the hydrogen is replaced by carbonic oxide. 
GEOLOGY AND PALAEONTOLOGY. 
Colliery Explosions and the Barometer. — Mr. J. Rofe writes to the Geo- 
logical Magazine , and shows that colliery proprietors have only to watch the 
barometer, and provide, in accordance with its indications, for the supply of 
air to the mines. Alluding to the well-known u Blowing well ” of Preston, 
in Lancashire, he states that, some time since, in a well recently constructed 
by him as a cesspool to some chemical works, he observed the phenomena 
characterising the 11 Blowing well.” When the atmospheric pressure 
diminished the air came from the well loaded, to a disagreeable extent, 
with the offensive vapour from the cesspool. On continuing his observa- 
tions with a barometer, he found similar results. He concludes, from these 
facts, that a coal-mine must be regarded as a gigantic well, from which, 
when the atmospheric pressure diminishes, the air expands, and rushes out 
with great violence. This circumstance is not, of itself, dangerous ; but if 
there be an excess of gas in the mine, and, at the same time, from accident 
or carelessness, a means of ignition, then, indeed, the consequences are very 
likely to be serious. Hence the barometer becomes the miner’s safest 
guide. 
