In the oil industry, the problem of crooked holes is second in importance only to the problem of overproduction. For many years we have known that exploratory core holes in mining regions may be crooked. For several years attention has been given to this matter in California, where numerous cases of crooked holes are on record. But only last year was a serious study made of the problem in the Mid-Continent. After describing several examples of crooked diamond drill holes, ordinary rotary holes, and cable-tool holes, the writer discusses the effects, measurement, and causes of the deviation of holes from the vertical, and the remedies suggested.

That we should do all in our power to study this problem, for the purpose of learning how to drill holes essentially vertical, is emphasized by the enormous losses in time and money which have been directly or indirectly attributable to crooked holes.