II. The optical deportment of the atmosphere in relation to the phenomena of putrefaction and infection

Abstract

An inquiry into the decomposition of vapours by light, begun in 1868 and continued in 1869, in which it was necessary to employ optically pure air, led me to experiment on the floating matter of the atmosphere. A brief section of a paper published in the Philosophical Transactions for 1870 is devoted to this subject. I at that time found that London air, which is always thick with motes, and also with matter too fine to be described as motes, after it had been filtered by passing it through densely packed cotton-wool, or calcined by passing it through a red-hot platinum-tube containing a bundle of red-hot platinum wires, or by carefully leading it over the top of a spirit-lamp flame, showed, when examined by a concentrated lumi­nous beam, no trace of mechanically suspended matter. The particular portion of space occupied by such a beam was not to be distinguished from adjacent space.