SCIENTIFIC.
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small particles are found which appear to be referable to common pyroxene of a yellowish colour, of active action in polarised light, and the extinction not taking place parallel to what seem to be the edges of the prism. Besides these minerals some corpuscles are found of hardly any action on polarised light, and sometimes full of globular concretions and other kinds of microliths, which, if seen in products of a volcanic region, I would not hesitate in considering of volcanic origin.
These are the principal substances which an investigation of the sediment of the snow which fell in Madrid on the 7th inst. have revealed, and though I am far from asserting that what appears to be foreign to the atmosphere of this part of the world should show these same substances floating in the atmosphere, there would be powerful reason for inferring that the gorgeous sunset of the past months have been brought about in consequence of that stupendous display of the volcanic forces of our globe.
It is already a remarkable coincidence that hypersthene should have been found both by MM. Daubree and Renard in their respective analysis of the ashes collected in the vicinity of Krakatoa.
JOSEPH MACPHERSON.
Madrid, December 22, 1883.
Mr. H. A. Cutler, printer of the University Courier, has placed in his office a Brayton Petroleum Engine. The first patent of this engine was issued several years ago, but only recently has it been put to practical use. The inventor has been engaged in improving his original for some time and at last has placed before the public almost a perfect little engine. A short time ago he placed it in the hands of a company, that will make a grand success of it.
The power is produced by the expansion of compressed air and vapor. Before the engine can be set in motion about forty
pounds of air has to be pumped into the air reservoir by hand, but after the reservoir is once filled, there will always be a sufficient amount of air in store to start the engine, unless from carelessness, the air is allowed to escape after the air pump stops.
The fuel is crude petroleum oil; this is pumped from a tank through a very small tube and saturates a wick placed in one end of the cylinder. The wick is ignited and a current of compressed air, which is passed in front of a diaphram, separating the wick from the main body of the cylinder, comes in contact with the blaze and is expanded. The vapor from the burning oil and the expanded air act in the same way that steam does in the cylinder of a steam engine; the only difference between the two being, the one is generated in the boiler the other in the cylinder itself.
The cylinder may be said to consist of two parts, the inner or cylinder proper and an outer covering with a space between the two through which cold water is pumped to prevent the heated air from heating the cylinder. About two barrels of water are necessary for running the engine ten hours, but none of the water is wasted and may be used over and over again. Almost the instant the oil is ignited the engine is going at the rate of 150 revolutions per minute, and in ten seconds it may attain a velocity of 300 revolutions per minute. No engineer is needed, for its governor attends to every thing necessary to keep its piston in motion. A two horse power engine (large enough to furnish power sufficient to run quite a large printing office) will consume three to four gallons in ten hours, running to its utmost capacity, at a cost of thirty-five to forty cents.
During the recent cold weather the center of the East River Bridge was, by the contraction of its metal, elevated three feet above its normal height.