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 

 Imown, 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 is a rabid gas. It combines with all metals, and explo- 

 sively with some, sodium, potassium, calcium, magnesium, and 

 aluminium becoming heated to redness by it. 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 contact 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 

 lOOlbs. 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 gns 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 

 mouth 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 401bs. is sufficient for a locomotive of the largest 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 music. The 



