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38 Tuesday May 9th 1843 Chemical Emination Tried the last experiment again. The plate with the different substances as before was exposed to the diffuse light of the sky. for 25 seconds, all the openings produced spots on the plate but those under the mica, and salt appeared a little less intense. The experiment must be repeated several times, inorder to bring out the facts relative to the specific influence of the different screening substances. Repeated the same experiment again with the same arrangement, the plate was exposed however during 12 seconds instead of 25. The result was that no difference could be perceived in the intensity of the impressions from the different openings. The impressions were as vivid as in any of the other experiments, although the light was gradually declining. Repeated the same experiment, the time of exposing the plate to the light, being 7 seconds. The spots were well developed on the plate, but no difference or very little, could be observed. One + 4 [[underlined]]ie[[/underlined]] the salt and the mica, appeared rather more blue than the others. In the foregoing experiments, the plate has been coated first with the vapour of iodine, and then to render it more sensible, has been placed over the vapour of the clo[[hole in page]]e of iodine. Inorder to decrease the sensibility of the plate, the exposure to the [[clornette?]] was omitted, and the plate exposed during about 10 seconds to the light of the sky. The impressions all came out as strong as before, the one under the glass being the more intense if anything. [[end page]] [[start page]] Wednesday May 10th 1843 [[underlined]]Chemical emination[[/underlined]] 39 Repeated the experiment with the plate prepaired as in the last experiment, the time was shortened to [[underlined]]6[[/underlined]] seconds. The light however is gradually diminishing. The plate again received an impression from each opening, the one under the glass was apparently the most intense although they were all faint. The light at the last experiment was quite faint, the sky was cloudy [[illegible strikeout]] the clock struck 6 at the time of the experiment. From all the results obtained this afternoon, it would appear that the phosphorogenic emination, and the chemical are as distinct as the luminiferous and the calorific. [[dividing line across page]] [[underlined]]May 10th[[underlined]] It is will known that when a discharge of electricity is passed through an orange, an egg, or an apple, and even through the thumb, the whole interior of the substance becomes illuminated by a phosphorescent red light. Made some experiments to day, or rather this morning, on the penetrating power of the light from the electrical discharge. 1 Four cakes of about one 4th of an inch in thickness of white wax was placed on a stand, before the spark from a Leyden jar, as in the arrangement [[image]] of the margin, and then the light observed through. The effect was beautiful and brilliant, the whole surface of the wax appeared to be illuminated with a white light. The experiment is a good class exhibition. I next placed a tube of pasteboard in front of of the wax and the eye at the other end, the effect with this was still more striking. The result could be seen without closing the windows. [[end page]]
