Elements of physics or natural philosophy, general and medical : written for universal use ... / by Neil Arnott.

  • Neil Arnott
Date:
1833
Catalogue details

Licence: Public Domain Mark

Credit: Elements of physics or natural philosophy, general and medical : written for universal use ... / by Neil Arnott. Source: Wellcome Collection.

    48/344 page 40
    the changes, he noted the number of degrees which the thermometer rose (as seen in the table which here follows) and thus ascertained the radiating power of each soit of covering. Lamp black 100° Writing paj)er 98 Crown glass 90 Ice 87 Isinglass 7*5 Tarnished lead 45 Clean lead 19 Iron polished 15 Tin plate 12 Gold, silver, and copper 12 He next reversed the experiments by using his hot-water vessel always in the same state, and covering the thermometer bulb with the different substances and colours, and thus he ascertained that the comparative absorbing powers of the sub- stances and colours were very nearly proportioned to their radialing powers : lamp-black, for instance, absorbed or was heated 100^, while the polished metals absorbed, or were heated only 12°, and so for the others. And, lastly, the absorbing powers being an indication of the opposite or rejiecting powers (for a body absorbing only a given pro- portion of the heat which falls on it, must reflect the remainder), he by the same experiments ascer- tained the radiating, absorbing, and reflective or mirror powers of the bodies, and therefore all the important points respecting radiant heat in its re- lation to them. . It seems paradoxical that the putting a clothing
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