Not excepting even the credulous Kraus (see his De Selby’s Leben), all the commentators have treated de Selby’s disquisitions on night and sleep with considerable reserve. This is hardly to be wondered at since he held (a) that darkness was simply an accretion of ‘black air’, i.e., a staining of the atmosphere due to volcanic eruptions too fine to be seen with the naked eye and also to certain ‘regrettable’ industrial activities involving coal-tar by-products and vegetable dyes; and (b) that sleep was simply a succession of fainting-fits brought on by semi-asphyxiation due to (a).
