ArT, XIV.—A CONTRIBUTION TO THE THEORY OF EARTHQUAKES 
—By Rev. Mytron Maury, D. D. 
(Received Sept. 15th, 1890. ) 
Trifling facts very frequently involve exceedingly important 
conclusions. The Fraunhofer lines which, to the observer, were 
mere meaningless curiosities, involve and have suggested the 
marvellous and prodigiously interesting laws of spectroscopic 
analysis; and the curious and once inexplicable phenomena 
which puzzled, not Fraunhofer alone, but for a long time such 
investigators as Brewster and Draper, are at this moment enabling 
us to explain the question, What are the stars made of? I need, 
I think, offer no further apology for asking the attention of this 
Society to a very insignificant fact which was brought to my 
notice on the occasion of a recent visit to the Steel Works at 
New Glasgow. A charge had just been drawn from the furnace, 
and the foreman was standing with me watching the process of 
casting the large ingots of steel. The pot, into which the molten 
steel was allowed to flow from the furnace, was provided with a 
hole in the bottom to permit the molten steel to pass into the 
casting moulds, and these were ranged in a row underneath a 
rail track, along which track the pot with its contents of 18 tons 
of melted steel was made to pass. One after another of these 
moulds was filled by the opening of the hole in the bottom of the 
pot. The necessary opening and closing of this hole were accom- 
plished by the elevation and depression of a larger stopper cased 
with fire clay. The foreman observed how needful it was that 
the casing of fire clay should be thoroughly dried before use. 
On one occasion the upper portion had been very slightly damp. 
As soon as the white hot metal and floating slag filling the pot 
had reached the damp portion, instantly an explosion occurred. 
Suddenly, a certain very small quantity of moisture—only a few 
drops, indeed—had been enclosed by the rising mass of metal 
and slag as it rapidly filled the pot. The temperature of that 
moisture was raised to a point above 2,000 degrees Fahr. We 
know what occurs when the boilers of a racing Mississippi 
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