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الصفحة 274 - Its parts, indeed, are few, but frequently repeated ; and, though it contains many wheels, yet only a few of them, move at the same time, so that its simplicity is greater than that of many machines in common and constant use. There is one circumstance in the construction of this machine, which is of considerable importance in making larger ones, viz. that, though its wheels are numerous, yet, by a peculiar contrivance, any error produced by accident, or by a slight inaccuracy in one of them, is...
الصفحة 202 - ... he took his own pocket-knife, and on trying to swallow it " it slipped down his throat with great ease, and by the assistance of some drink and the weight of the knife," it was conveyed into his stomach. The spectators, however, were not satisfied with one experiment, and asked the operator " whether he could swallow more ?" his answer was, " all the knives on board the ship ;" upon which, three knives were immediately produced, which were swallowed in the same way as the former ; and, "• by...
الصفحة 241 - ... horizontal position for two or three days, that this substance may penetrate. After this it may be dried ; and it is only further necessary to wipe and ventilate it occasionally, to prevent mouldiness. A...
الصفحة 358 - ... combination with part of the metal and the charcoal, and forms an inflammable compound not acted upon by the acid. Some striking effects are produced by the action of nitric acid on these powders. If that from pure steel be taken, it is entirely dissolved ; and such is also the case if the powder be taken from an alloy, the metal of which is soluble in nitric acid ; but if the powder is from an alloy, the metal of which is not soluble in nitric acid, then a black residuum is left not touched...
الصفحة 358 - ... protoxide of iron, and the alloying metal. Hence, during the action of the acid on the steel, a portion of hydrogen enters into combination with part of the metal and the charcoal, and forms an inflammable compound not acted upon by the acid. Some striking effects are produced by the action of nitric acid on these powders. If that from pure steel be taken, it is entirely dissolved; and such is also the case if the powder be...
الصفحة 159 - ... all the phenomena accord entirely with the supposition that the earth's atmosphere is of finite extent, limited by the weight of ultimate atoms of definite magnitude no longer divisible by repulsion of their parts.
الصفحة 277 - ... furnished to the third section the proper differences at the stated intervals. They also received from that section the calculated results, and compared the two sets, which were computed independently for the purpose of verification. The third section, on whom the most laborious part of the operations devolved, consisted of from sixty to eighty persons, few of them possessing a knowledge of more than the first rules of arithmetic: these received from the second class certain numbers and differences,...
الصفحة 211 - This took place on the 4th of December, 1805, and in the course of that night he swallowed five knives. On the next morning the ship's company, having expressed a great desire to see him repeat the performance, he complied with his usual readiness, and " by the encouragement of the people, and the assistance of good grog...
الصفحة 361 - We would farther recommend, that this act of tempering be performed twice ; that is, at the usual time before grinding, and again just before the last polish is given to the blade. This second tempering may perhaps appear superfluous, but upon trial its utility will be readily admitted. We were led to adopt the practice by analogy, when considering the process of making and tempering watch springs.
الصفحة 351 - With platina and rhodium, steel combines in every proportion ; and this appears also to be the case with iridium and osmium : from 1 to 80 per cent* of platina was perfectly combined with steel, in buttons of from 500 to 2000 grains. With rhodium, from 1 to 50 per cent, was successfully used. Equal parts by weight of steel and rhodium, gave a button, which, when polished, exhibited a surface of the most equisite beauty : the colour of this specimen is the finest imaginable for a metallic...