the act of attenuating; that is, of making any fluid thinner, and less consistient, than it was before. The word is compounded of ad, 'to,' and tenuis, 'thin.' Attenuation is defined more generally by Chavín, the dividing or separating of the minute parts of any body, which before, by their mutual nexus or implication, formed a more* continuous mass. Accordingly, among alchemists, we sometimes find the word used for pulverization, or the act of reducing a body into an impalpable powder, by grinding, pounding, or the like.