Kirchhoff's law of thermal radiation rarefied material such as air, or transparent material, through which observations can be made. The interface is not a material body and can neither emit nor absorb. It is a mathematical surface belonging jointly to the two media that touch it. It is the site of refraction of radiation that penetrates it and of reflection of radiation that does not. As such it obeys the Helmholtz reciprocity principle. The opaque body is considered to have a material interior that absorbs all and scatters or transmits none of the radiation that reaches it through refraction at the interface. In this sense
A Changed Man and Other Tales to be sold in October 1913. A Changed Man and Other Tales A Changed Man and Other Tales is a collection of twelve tales written by Thomas Hardy. The collection was originally published in book form in 1913, although all of the tales had been previously published in newspapers or magazines from 1881 to 1900. There are eleven short stories and a novella "The Romantic Adventures of a Milkmaid". At the end of the book there is a map of the imaginary Wessex of Hardy's novels and poems. Six of the stories were published before 1891 and therefore lacked international