The Philosophical magazine; a journal of theoretical, experimental and applied physics . ough metallic surface is dependent on the angleswhich the surface makes with the incident rays. jM. Knoblauchnext examined whether the quality of the heat reflected wasaffected by the inclination. The experiment was first made witha dull surface of gold, and the result was, that the rays retlectedfrom it at an inclination of 80° were more caj)able of passingthrough the yellow and red glasses than rays reflected at an in-clination of 2°. The following Table contains the results of theexperiments:— upon Radi
The Philosophical magazine; a journal of theoretical, experimental and applied physics . ough metallic surface is dependent on the angleswhich the surface makes with the incident rays. jM. Knoblauchnext examined whether the quality of the heat reflected wasaffected by the inclination. The experiment was first made witha dull surface of gold, and the result was, that the rays retlectedfrom it at an inclination of 80° were more caj)able of passingthrough the yellow and red glasses than rays reflected at an in-clination of 2°. The following Table contains the results of theexperiments:— upon Radiant Heat. 373 Gold. j Inclination. Yellow glass. | Red glass. Rough surface 802 100 : 70 100 : 55100:66 100:51 802 100:71 100:57100:66 100:50 Uureflected heat 80 100:65 1 100:50 2 We see here that the qualitative difference, in the case of heatreflected from a roughened surface of gold, disappears whollywhen the rays fall upon the plate at a very small angle. Similar experiments were made with silver, mercury, copperand brass : the results are collected in the following Table;—. In all these cases the qualitative peculiarity which distinguishes 374 On the Influence of Metals upon Radiant Heat. heat diffusely reflected, from the unrcflected heat, disappearswhen the incidence is very obHque. It is thus placed beyonddoubt, that the properties of the reflected rays are dependent on theinclination at ivhich they meet the reflecting surface. The principal results of this investigation may he stated to beas follows:— 1. INIetals, as gold, silver and platinum, when in thin layers,are to be regarded as diathermanous bodies, which permit a por-tion of the calorific rays to pass through them -, which portionnaturally becomes less as the thickness of the layer increases. In thus transmitting the calorific rays, certain metals, as goldand silver, exercise an elective absorption, similar to that of co-loured transparent bodies upon light. Others, on the contrary,like platinum, act in
Size: 1492px × 1674px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookids, bookpublisherlondontaylorfrancisetc, booksubjectphysics
