I ID you know that friction is not the only cause of cylinder wear ? CORROSION,

like rust, eats away the metal. If your cylinders were made of stainless steel they would resist corrosion — just as a stainless steel knife resists rust and acids. And if your cylinders lasted longer you would use less oil, get less carbon and postpone expensive reboring.

But cylinders are not made of stainless steel, the secret of which is chromium. So Wakefield have at last perfected an oil which gives the same effect.

Wakefield PATENT Castrol is the famous Castro! plus a “soluble chromium stabiliser” which eliminates corrosion. As though this were not enough, yet another brilliant technical success has been gained. You know how oil discolours in use, indicating the formation of oxidised substances, which eventually become sludge or gum ; this is because

the oil absorbs oxygen when churned up in a hot engine. In PATENT Castrol the deterioration has been delayed by a “tin-derived inhibitor” which opposes the combination of oxygen with the oil in use.

Independent proof of this two-fold triumph will be published. If you would like full technical details, please send the coupon. Better still, prove it to your own satisfaction by beginning to use PATENT Castrol to-day, It conquers corrosion as Castrol masters friction. There is a suitable grade for every type of engine.