HUMIDITY, that quality in bodies by which they are capable of wetting other bodies. This differs very much from fluidity, and seems to be merely a relative thing, depending on the congruity of the component particles of the liquor to the pores of such particular bodies as it is capable of adhering to, penetrating a little, or wetting. Thus, for instance, quicksilver is not moist with regard to our hands or clothes, but may be called so in reference to gold, tin, or lead, to whose surfaces it will perfectly adhere, and render them soft and moist.