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In the gymnotus and torpedo they no doubt serve as powerful means of defence, and perhaps for securing prey; yet in the ray, as observed by Matteucci, an analogous organ in the tail manifests but little electricity, even when the animal is greatly irritated; so little that it can hardly be of any use for the above purposes.
M. Matteucci also observed at Pisa, during the appearance of a brilliant aurora borealis, decided signs of positive electricity in the air; but of all phenomena, those which invariably take place at the same time as the appearance of the aurora borealis are the magnetic effects.
Barsanti and Matteucci were engaged in devising and experimenting with an engine very similar to this some years before, but Otto & Langen, no doubt, worked quite independently. Barsanti's engine never became a commercial article; while Otto & Langen's firm, it is said, held their own for ten years, and turned out about 4000 engines.
The electric organs of fishes offer another case of special difficulty; it is impossible to conceive by what steps these wondrous organs have been produced; but, as Owen and others have remarked, their intimate structure closely resembles that of common muscle; and as it has lately been shown that Rays have an organ closely analogous to the electric apparatus, and yet do not, as Matteucci asserts, discharge any electricity, we must own that we are far too ignorant to argue that no transition of any kind is possible.
It is pretty well known that researches by Matteucci, Du Bois-Reymond, and others, have made us acquainted with the influence of electricity and galvanism on the muscular system of animals, and that important physiological effects have been attributed to this influence, more than perhaps we are warranted in assuming in the present state of our knowledge.
It was on Saturday, the 7th, that Bosco Trecase became the prey of the river of molten rock. During that night and the following day the crisis of the eruption came. The observatory on the mountain side was occupied by Professor Matteucci, his assistant, Professor Perret, of New York, and two domestics, all others having been sent away.
The electric organs of fishes offer another case of special difficulty: It is impossible to conceive by what steps these wondrous organs have been produced; but, as Owen and others have remarked, their intimate structure closely resembles that of common muscle; and as it has lately been shown that rays have an organ closely analogous to the electric apparatus, and yet do not, as Matteucci asserts, discharge any electricity, we must own that we are far too ignorant to argue that no transition of any kind is possible. pp. 192-3.
It is interesting to learn that two men stood heroically to their post of duty during the whole scene of the explosion, Professor Matteucci, Director of the Royal Observatory, and his American assistant, Professor Frank A. Perret, of New York.
Evidently Vesuvius had no terrors for these case-hardened veterans. We have already told the story gleaned by the correspondents from the daring scientists. Matteucci completed his record of boldness on Friday, the 13th, by climbing to a point far above the observatory, at the imminent risk of his life, to observe the conditions then existing.
The return stroke is accomplished by the atmospheric pressure, and the work is now done upon the engine shaft on the return only. The method of connecting on the return stroke while leaving the piston free on the out stroke varies, but in many engines the principle was the same. Barsante and Matteucci, year 1857, British patent No. 1,625, describe the first engine of this kind, but Messrs.
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