<div class="htmlview paragraph"><b>OXIDATION of lubricating oils produces, among other products, oxyacids, which, according to the study made by these authors, constitute the source of ring sticking because of a tendency to turn into insoluble deposits.</b></div> <div class="htmlview paragraph"><b>The chemical explanation of this phenomenon is given here in detail, so that it may prove useful in implementing the design of noncorrosive, anti-ring-sticking additives for heavy-duty oils.</b></div>