Notices of the Proceedings at the Meetings of the Members of the Royal Institution, with Abstracts of the Discourses, 13. sējums

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W. Nicol, Printer to the Royal Institution, 1893
 

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116. lappuse - ... from each other, and appear as the same colour, but of different luminosity. Prior to reflection, and still more, prior to experience, we should be apt to conjecture that the existence of colour-blindness in any individual could not remain concealed, either from himself or from those around him ; but such a conjecture would be directly at variance with the truth. Just as it was reserved for Mariotte, in the reign of Charles II., to discover that there is, in the field of vision of every eye,...
129. lappuse - ... hardly any invention associated with the present century which has rendered more splendid services in every department of science. The physicist and chemist, the astronomer and geographer, the physiologist, pathologist, and anthropologist will all bear witness to the value of photography. The very first scientific application of Wedgwood's process was made here by the illustrious Thomas Young, when he impressed Newton's rings on paper moistened with silver nitrate, as described in his Bakerian...
5. lappuse - I was very anxious that he should devote his life to science, and persuaded him to become a candidate for the Professorship of Natural Philosophy at St Andrews. He was on the point of securing this, but his personal slight deformity ! was an objection in the eyes of one of the electors, and St Andrews lost the glory of having one of the greatest discoverers of our age.
454. lappuse - B turns backwards, ie in the opposite direction to the rotation imposed upon A. This is the current induced in a secondary circuit when an electromotive force begins to act in the primary. In like manner, if A, having been for some time in uniform movement, suddenly stops, B enters into motion in the direction of the former movement of A. This is the secondary current on the break of the current in the primary circuit. It might perhaps be supposed by some that the model was a kind of trick.
454. lappuse - Faraday did not light upon truth without delay and difficulty. One of Faraday's biographers thus wrote: — " In December 1824, he had attempted to obtain an electric current by means of a magnet, and on three occasions he had made elaborate and unsuccessful attempts to produce a current in one wire by means of a current in another wire, or by a magnet. He still persevered, and on August 29, 1831...
128. lappuse - Michael Faraday. In the same month he communicated his first paper on a photographic process to the Royal Society, and in the following month he read a second paper before the same Society, giving the method of preparing the sensitive paper and of fixing the prints. The outcome of this work was the
126. lappuse - THE history of a discovery which has been developed to such a remarkable degree of perfection as photography has naturally been a fruitful source of discussion among those who interest themselves in tracing the progress of science. It is only my presence in this lecture theatre, in which the first public discourse on photography was given by Thomas Wedgwood at the beginning of the century, that justifies my treading once again a path which has already been so thoroughly well beaten. If any further...
135. lappuse - All this looks like chemical change, and not physical modification pure and simple. 1 have in this discourse stoically resisted the tempting opportunities for pictorial display which the subject affords. My aim has been to summarize the position in which we find ourselves with respect to the invisible image after fifty years' practice of the art. This image is, I venture to think, the property of the chemist, and by him must the scientific foundation of photography be laid. We may not be able to...
246. lappuse - But while crystals resemble ourselves in ''growing old," and, at last, undergoing dissolution, they exhibit the remarkable power of growing young again, which we, alas! never do. This is in consequence of the following remarkable attribute of crystalline structures. It does not matter how far internal change and disintegration may have gone on in a crystal ; if only a certain small proportion of the unaltered molecules remain, the crystal may renew its youth and resume its growth. When old and...
374. lappuse - ... the surface tensions. But we sometimes find crystals with only half the modifications required for symmetry. In such cases the surface tensions must produce a stress in the interior tending to deform the molecules. When the crystal was growing there must have been equilibrium, and therefore a pressure equal and opposite to this effect of the surface tension. There are various ways in which we may suppose that such a force would arise.

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