Mémoire sur la propagation de la Chaleur dans les Corps.

(Upsal, C.A. Leffler, 1860). 4to. Orig. printed wrappers. Extracted from ""Actes de la Soc. Roy. des Sciences d'Upsala"", Series 3ieme. T. III. Pp. (51-) 72. This extract has the orig. printed wrappers from Tome III.

-
First edition of Ångström's importent paper on the transformation of heat through materials. Angstrom determined the conductivity of the material of a bar by periodically heating and cooling it. The bar was heated and cooled periodically by passing steam and water at regular intervals through a chamber at one end of the bar ... In this way, the temperature at points along the bar fluctuate periodically and on account of surface radiation the temperature amplitude diminishes as the distance from the region of supply increases.In 1868, Ångström created a spectrum chart of solar radiation that expresses the wavelength of electromagnetic radiation in the electromagnetic spectrum in multiples of one ten-millionth of a millimetre, or 1×10-10 metres. This unit of length later became known as the ångström, Å.