Note 22 — ADDENDA.
Reading edition
The two sentences which, in the text, precede the asterisk, I have introduced while these pages are standing in type: being led to do so by the perusal of some notes kindly lent to me by Prof. Dewar, containing the outline of a lecture he gave at the Royal Institution during the session of 1880. Discussing the conditions under which, if "our so-called elements are compounded of elemental matter", they may have been formed, Prof. Dewar, arguing from the known habitudes of compound substances, concludes that the formation is in each case a function of pressure, temperature, and nature of the environing gases.