5 
of the earth is subjected at a depth of 70,000ft.—and has found 
that, with metals, moisture retards the action, but with soluble 
substances, whose bulk is less when dissolved, the action is quick- 
ened. ‘These experiments are of great value when considering the 
formation of the geological strata, as in the subterranean laboratory 
of nature pressure is always operating. 
One of the three great ‘‘Arcana,” vainly sought by alchemists, 
has at last been discovered by modern chem‘stry. I allude to the 
* Universal Solvent,” the Element Fluorine, which has long been 
known, but only lately separated, and cannot even now be retained, 
because it attacks everything. It exists peacefully associated with 
calcium in Fluor Spar, and in a few other compounds, but when 
isolated it isa rabid gas. It combines with all metals, and explo- 
sively with some, sodium, potassium, calcium, magnesium, and 
aluminium becoming heated to redness byit. Iron filings and 
manganese burst into brilliant scintillations when exposed to it— 
glass it devours at once, and water ceases to be water when brought 
into contaet with it, the gas combining with its hydrogen and 
forming hydrofluric acid. 
In America the utilization of natural gas is being developed. At 
Findley, Ohio, a well was bored, which yielded at first eight million 
cubic feet of gas per day, and as it escapes at the high pressure of 
100lbs. to the square inch, it is well adapted for conveyance by 
pipes to a long distance. In the ‘‘ Hebburn” Colliery, near New- 
castle, a large ‘‘ blower’’ of gas, which had been a source of great 
trouble, is now drawn off pipes and utilised for heating boilers, thus 
saving both fuel and labour. 
A satisfactory method of burning petroleum as fuel has been dis- 
covered by Mr. Thomas Urquhart, previous attempts having merely 
resulted in burning the vapour of the oil. or in turning the oil into 
a gas and burning that. In Mr. Urquhart’s scheme the petroleum 
becomes by means of a forcible jet of steam or air, a fine spray, 
which is itself really burned asfuel. The contrivance consists of two 
tubes. the inner one containing the steam or air, and the outer one 
the oil, the outer tube being longer than the inner one so that when 
the air and the oil are simultaneously projected, they combine and 
are together burned on a fire-brick furnace, towards which the 
thouth of the tubes open. The minutest particles of oil are in this 
way consumed, and the fire-brick becomes so intensely hot that it 
radiates heat to all parts of the fire-box, and serves to rekindle the 
oil after it has been shut off for a time. A spray producer weigh- 
ing 40lbs. is sufficient for a locomotive of the Jargest size. 
The development of the Phonograph seems likely to be of great 
practical use; in its latest form it is capable of reproducing sounds 
from a whistle to a shout, or from saw-filing to band musie, The 
