Journal - Franklin Institute of the State of Pennsylvania (1826)
Franklin Institute, Philadelphia, Franklin Institute (Philadelphia, Pa.) · [Philadelphia : Franklin Institute] · leaf 406
extreme has the shapeof a coma, which in this case is di-rected downwards. If we reverse thelens, as in the next figure, so that theincident rays fall on the convex side,the coma is directed outwards. We see,we have here, by reversing the lens,opposite comas; and such lenses of op-posite character… … ON THE DEVELOPMENT OF THE CHEMICAL ARTS DURING THE LAST TEN YEARS.* By Dr. A. W. Hofmann. From the Chemiral News.[Continucfl from Vol. ci, page 270.] The author remarks in a note that the number 21 for ice and saltsignifies the permanent temperature below 0°, which is observed tillthe whole mixture…
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