SCIENTIFIC SUMMARY. 
313 
strongly opposed by Mr. G. P. Scrope, in a recent number of the Geologicol 
Magazine. After enumerating a variety of facts, he says, that such facts 
have brought him to the conviction that though there may be occasionally 
lateral flows of lava beneath the surface of a volcano, from an interior pool, 
through fissures opening outwards at a lower level — as in the tajopings of the 
lake of Kilauea, so frequently witnessed — yet, in general, lava solidifies so 
rapidly and readily from increase of pressure or diminution of temperature, 
that no very extensive accumulations of such matter in a fluid state are 
likely to exist even beneath an active volcano, still less below vaster areas 
of the earth’s crust, and that the apparent connection of one volcanic vent 
with others in its neighbourhood, or belonging to the same chain, is rather 
due to the lateral transmission or escape of heat than to the actual transfer- 
ence of liquid matter between one and the other. Many facts tend to show 
that ‘Gava,” the only fused rocky matter in nature with which we are 
acquainted, is, when it issues from the interior of the earth during volcanic 
eruptions, extremely viscous ; and though some currents are seen to How 
down an incline so low as 6° or 8° with a velocity of three or four miles an 
hour, others are so sluggish as to accumulate in bulky masses beside or over 
the orifice whence they are expelled. If,” says Mr. Scrope, “ it be suggested 
that in the depths of the volcano the fluidity of the lava is probably very 
much greater, owing to its higher temperature, this idea is, I think, incon- 
sistent with many well-known facts, such, for example, as the occasional 
efflux of liquid lava from the summit of Mauna Loa in Hawaii, while that 
in the crater of Kilauea at a level of 10,000 feet lower, and only sixteen 
miles distant, remains unaffected.” 
MECHANICAL SCIENCE. 
New Rifle . — After a long and laborious investigation, the Ordnance Select 
Committee have recommended the adoption by Government of the Martini- 
Henry rifle, in place of the Snider rifle now used. The former has only 
twenty-seven pieces in the breech against thirty-nine in the latter j the 
arrangement of the parts is stronger; the manipulation more simple, and 
the cost less. The Martini-Henry rifle of 0-45-inch bore, has a much lower 
trajectory than the 0-5-inch and 0-577-inch Snider, it is more accurate 
especially at long range, and the penetrating power of its bullet is 
greater. 
Liquid Fuel . — Captain Selwyn has published the results of further experi- 
ments on the use of liquid fuel. Although Captain Selwyn does not appear 
to maintain the exaggerated estimate of the evaporative duty of liquid fuel 
which he once entertained, he still seems to think that the whole theoretical 
heat of combustion may be utilised. So far as the experiments go, it has 
not yet been shown that in the ordinary conditions of practice a pound of 
liquid fuel will evaporate more than fifty per cent, more water than a pound 
of the best coal properly burnt. Some other applications of liquid fuel pos- 
sess much interest. Boiler-plate heating furnaces at "Woolwich and Chatham 
have been fitted with Messrs. Dorsett and Blyth’s apparatus, already de- 
