Adsorption Properties of Hair 348 Figure 14 shows the same rate data, but this time plotted together with the weight increase (i.e. the amount adsorbed) that occurs during each humidity step. The two curves mirror each other closely and suggest that longer adsorption times arise when higher levels of adsorption take place. This relationship appears to hold true when the magnitude of the relative humidity steps remain constant however, Figure 15 shows results for increasing the relative humidity from zero to progressively higher values (0–10%, 0–20%, 0–30% and so on). Obviously these larger steps give rise to higher moisture adsorption yet the half-times decrease with increasing step size (i.e. faster adsorption occurs). In short, it appears that larger shifts in atmospheric moisture content lead to faster re-equilibration times. We have subsequently discovered a reference from the wool literature in 1955 that reached this same conclusion.17 There are additional factors that confound an understanding of the kinetic aspects of water adsorption by hair. As may be expected, Figure 13. Half-times for steps in relative humidity from Figure 10