Journal of the Franklin Institute

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Pergamon Press, 1849
 

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Seite 131 - ... an outer cylinder of glass, closed at the top by a plate of mica, g ; or, still better, by two plates of mica, one resting on the top of the glass, and the other one, h, dropping a short way into it.
Seite 285 - I conceive, right to add, that in all cases, even though the composition of the water seems to bring it within the conditions of safety now stated, an attentive examination should be made of the water after it has been running for a few days through the pipes ; for it is not improbable that other circumstances, besides those hitherto ascertained, may regulate the preventive influence of the neutral salts.
Seite 145 - The Committee on Science and the Arts constituted by the Franklin Institute of the State of Pennsylvania, for the promotion of the Mechanic Arts, to whom was referred for examination a Solar Compass, invented by WM.
Seite 355 - ... by sixteen iron screws four and a half inches in diameter. This platform has several shores on its surface, which were brought to bear equally on the vessel's bottom, to prevent her from canting over on being raised out of the water. About thirty men...
Seite 126 - There existed large quantities of haematite in Great Britain, equal in quality to that of Nassau, or of the Hartz mountains, from which so much iron was made, for converting into steel. The mines of Ulverstone alone now produce 50,000 tons annually, and at least 25,000 tons more could be shipped from Cornwall ; and if a demand existed, there was scarcely a limit to the quantity that could be raised. He apprehended that the iron made by this process could be converted into good steel : this was very...
Seite 335 - ... received, in order to give the work a good appearance. In order to test this, Mr. Nasmyth subjected two pieces of cable bolt iron to 160 blows between swages, and afterwards annealed one of the pieces for a few hours. The unannealed piece broke with five or six blows of a hammer, showing a crystallized fracture ; while the annealed piece was bent double under a great number of blows, and exhibited a fine fibrous texture. The fact of the fibre being restored by annealing was well understood and...
Seite 331 - From the black powder obtained as above, the palladium is extracted by resolution in nitric acid and super-saturation with ammonia, by which the oxides of palladium and copper are first precipitated, and then redissolved, while those of iron, lead, &c., remain insoluble. To the clear ammoniacal solution, muriatic acid is then added in excess, which occasions a copious precipitation of the yellow ammonio-chloride of palladium, from which, after sufficiently washing it with cold water and ignition,...
Seite 114 - So on copper coated with mercury, the mercury in such case no doubt readily tarnishing (see section 7, polished surfaces not receiving spectra). Having decided that the effect in question is due neither to light nor heat, to what cause, it may be asked, is it to be ascribed ? Conclusions. — Istly, As brightness of the plate is indispensable, and with brightness must exist an increased tendency to tarnish, or enter into chemical combination ; 2ndly, as the plate must be of an oxidable metal, and...
Seite 115 - As the more perfectly the coins are cleaned and dried,* the less the effect, and as a dry perspiration (so to call it) must exist in a greater or less degree on all coins, since they pass through so many hands, and as perspiration is slightly acid. 4thly. As even with clean coins the effectt by actual contact must be admitted, but still is greater when there is a difference in the naturej of the metal ; and Sthly.
Seite 206 - Mechanical flight seems more adapted for use on a much smaller scale, and for less remote distances; serving, perhaps, the same purpose that a boat does to a ship, each being essential to the other.

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