Petroleum as it occurs in Nature is a very complex mixture of hydrocarbons. Imagine a mixture of petrol, paraffin, gas oil, fuel oil and lubricating oil, together with a certain amount of water and other foreign matter, and you have an idea of crude petroleum as it is found in Nature.

It is interesting to note that practically the sole use of petroleum for some time after the first well was drilled was as a burning oil. The object of the refiner was therefore to produce as large as possible a percentage of paraffin from his crude. The lighter fractions were regarded as a necessary evil, and it became a very difficult problem to dispose of them satisfactorily. It was, of course, necessary to keep the flash point of the paraffin high enough to avoid the danger of explosion of the lamps in which it was used. Petroleum inspectors were employed to ensure that the paraffin on sale was not “adulterated” with the then valueless light petroleum spirit. No market other than as a source for lighting gas was found for this light spirit until the advent of the motor car.