All distillates of petroleum have to be treated with acid and alkali to refine them.
The migration of the distillates to suitable underground reservoirs is responsible for the accumulation of oil and gas pools.
The distillates have migrated to their present positions under pressure of ground-waters.
For the purpose of collecting the distillates in fractions, many forms of receivers have been devised.
The distillates were collected in successive fractions, and the furfural and volatile acid determined.