Which is the boy? You can be sure of SHELL 'I At first glance you would think they were all girls. Look again and you will see that the one on the left is a boy. Petrols look the same, but Shell has a distinction which is quickly re vealed in use. WHY SHELL SUITS THE MODERN ENGINE. All motor spirit consists of atoms of hydrogen and carbon. In ordinary petrol, these atoms take the form of long chains, in which formation they combine irregularly with the oxygen from the carburettor. This can produce rough running and "pinking" in the modern engine. Shell rearranges these atoms into compact groups by the "re-forming" process. In this formation they combine evenly with the oxygen. Thus combustion is controlled and "pinking" prevented.

Modern Publicity en | 1937 | | page 47