human
are (1) making the liquor
gpt
_i.e._ adding alkali to neutralize much of the free acid, which involves a considerable reduction in the stabilizing effect of the hydrions; (2) the adsorption of hydrions by the hide gel when first immersed in approximately neutral condition; (3) the operation of the
human
that the predominant ionic effect in discharging is due to the multivalent anions. In this case the divalent SO{4}-- ions assist materially in discharging the positive charge on the chrome sol; (4) the final process of neutralization in which still more alkali is added. The operation of the valency rule is the most complex of these factors, for there is also to be considered the stabilizing effect of the kations, especially of the trivalent kation Cr+++ from the unhydrolyzed chromium sulphate. It is quite possible also that in the last stages of chrome tanning there are