Experiments and observations on the light which is spontaneously emitted, with some degree of permanency, from various bodies. / By Nathaniel Hulme, M.D. F.R.S. and A.S. From the Philosophical Transactions.

  • Hulme, Nathaniel, 1732-1807.
Date:
1800
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Licence: Public Domain Mark

Credit: Experiments and observations on the light which is spontaneously emitted, with some degree of permanency, from various bodies. / By Nathaniel Hulme, M.D. F.R.S. and A.S. From the Philosophical Transactions. Source: Wellcome Collection.

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    was at once finely illuminated. On the next evening it ap¬ peared still very lucid; and likewise on the succeeding night. Exper. 4. The experiment was reversed. Half a dram of the salt, being dissolved in two ounces of water, had herring-light mixed therewith, so as to be made very luminous. On the addi¬ tion of two drams more of the salt, the lucidness was instantly destroyed : but the light was again recovered, by pouring eight ounces of cold water upon the extinguished luminous fluid. The revived light was very vivid the next evening. 4 Exper. 5. Two ounces of sea water were illuminated with mackerel-light, and then extinguished by adding two drams of common salt. The light was again restored, by diluting the so¬ lution with eight ounces of cold spring water. N. B. If the illuminated liquid be uncommonly brilliant, it may sometimes require more salt to extinguish the light com¬ pletely, than is here specified; in that case, the measure of water for dilution, must be always calculated in exact propor¬ tion to the weight of salt employed. SECTION VI. Spontaneous Light is rendered more vivid by Motion. EXPERIMENTS. Exper. 1. A quantity of illuminated liquid was poured into a broad vessel, which was placed in the laboratory. The next evening, on examination, it appeared to be quite dark. But a finger, or rod, being drawn through it, was followed by a lumi¬ nous line. Exper. 2. A phial, containing a pretty large portion of liquid impregnated with light, having been at rest a number of hours,