The London, Edinburgh and Dublin Philosophical Magazine and Journal of Science

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Taylor & Francis, 1847 - Physics

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Page 351 - I conclude that as the temperature of an incandescent body rises, it emits rays of light of an increasing refrangibility, and that the apparent departure from this law, discovered by an accurate prismatic analysis, is due to the special action of the eye in performing the function of vision.
Page 35 - Planet,' evidently showing the conviction in his own mind of the reality of its existence. Towards the end of the next month, a communication of results slightly different was made to the Astronomer Royal, with the addition of what was far more important, viz. a list of the residual errors of the mean longitude of Uranus, for a period extending from 1690 to 1840, after taking account of the disturbing effect of the supposed planet.
Page 188 - ... upper part of a lightning rod, erected in accordance with the formula given by the French Institute, corresponding sparks could be drawn from every part of the rod, even from that near the ground. In a communication since made to this society, I have succeeded in referring this phenomenon to...
Page 351 - As the luminous effects are undoubtedly owing to a vibratory movement executed by the molecules of the platinum, it seems from the foregoing considerations to follow, that the frequency of those vibrations increases with the temperature. In this observation I am led by the principle, that " to a particular color there ever belongs a particular wave-length, and to a particular wave-length there ever belongs a particular color ;" but in the analysis of the spectrum made by Sir D.
Page 346 - I had remained there a sufficient length of time to enable my eyes to become sensible to feeble impressions of light, I caused the current to pass, gradually increasing its force, until the platinum was visible. In several repetitions of this experiment it was uniformly found that the index to which the platinum was attached stood at the eighth division when this took place. The metal had therefore dilated...
Page 193 - Richman, of St. Petersburg, should be recollected, who was killed by a flash from a small wire, which entered his house from an elevated pole, while he was experimenting on atmospheric electricity. The danger, however, which has been apprehended from the electricity leaving the wire and discharging itself into a person on the road, is, I think, very small ; electricity of sufficient intensity to strike a person at the distance of eight or ten feet from the wire, would, in preference, be conducted...
Page 192 - ... without any transfer of the fluid from the cloud to the apparatus. The discharge between the two portions of the wire continued for more than an hour, when the effect became so powerful, that the superintendent, alarmed for the safety of the building, connected the long wire with the city gas pipes, and thus transmitted the current silently to the ground. I was surprised at the quantity and intensity of the current; it is well known, that to affect a common galvanometer with ordinary electricity,...
Page 357 - ... broad, ignited by the passage of a voltaic current, and placed in such a position that its dilatation could be measured by the movements of an index over a graduated scale. In fig. 7, ab represents the slip of platinum, the upper end of which is soldered to a stout and short copper pin a, firmly sunk in a block of wood c, which is immovably fastened on the basis dd of the instrument.
Page 348 - ... interesting to remark how nearly this point coincides with 1000° of the Fahrenheit thermometer, when Laplace's coefficient for the dilatation of platinum is used. Upon that coefficient the point of incandescence is 1006° F. In view of these considerations, and recollecting that the number given by Daniell is 980°, and that of Wedgwood 947°, I believe that 977° is not very far from the true temperature at which solids begin to shine. It is to be understood, of course, that this is in a very...
Page 357 - Further, it may be remarked, as illustrative of the same fact, that the increased quantity of heat radiated by a mass of platinum in passing from 1000° to 1300°, is nearly equal to the amount it gives out in passing from common temperatures up to 1000°.

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