Standard samples for thermometric fixed points

• Book ID: 104121405
• Publisher: Elsevier Science
• Year: 1917
• Tongue: English
• Weight: 94 KB
• Volume: 184
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/s0016-0032(17)90491-0

✦ Synopsis

THE reflecting power of tungsten and in the region of the spectrum from o. 5 to 6 l* was determined by comparison with silver, and by a new method employing' a total reflection prism. Four samples of tungsten in the form of plane, highly polished mirrors were examined.

The reflectivity of tungsten rises abruptly from 5o per cent. at o. 5 t* to 9o per cent. at e/*.

All samples of tungsten show sharp indentations at o.8 I* in the reflectivity curve. A similar indentation occurs at 1. 3 /* in the reflectivity curve of the pure metal, but not in an impure sample. The application of these data to the question of increasing the luminous efficiency is discussed.

The reflecting power of stellite rises from 65 per cent. in the visible to 88 per cent. at 9 ~. * Communicated by the Director. 1 Scientific Paper No. 308. * Circular No, 66.