Methods of well drilling differ in various regions in accordance with the special problems to be encountered and perhaps no other industry furnishes more examples of mechanical ingenuity in the solution of physical difficulties. Drake went about the business of drilling the first well by using the traditional methods of boring for salt. Improvement was inevitable, however, and the Canadian wells of Western Ontario, which came into existence almost contemporaneously with those of Pennsylvania, were fruitful of inventions which have influenced drilling practices in many parts of the world. If we go back to the origins of oil and salt drilling mechanisms we find ourselves in China centuries before the Christian era. The Chinese used an auger attached to a pole that was held in a vertical position from a cross pole supported on a post. The end of the cross pole was fastened to a lever while a driller guided the cable to which an auger or boring tool was attached. Several coolies jumped from a platform on to the reverse side of the board, so that the tool would be jerked up and would plunge down and thus deepen the hole with each stroke. The deeper the hole became, the more coolies required for the task of “kicking down.” Jumpers were not a part of the staff of an oil-drilling organization in America in the early days but foot power was sometimes employed for the same purpose of driving the drilling tools into the ground. To-day labour-saving machinery plays as great a part in well drilling as in other branches of industry. Let us suppose then that an oil company, or an individual with the requisite capital at his back, has advanced through the preliminaries which must precede drilling operations; the geologists have made a favourable declaration as to the prospective site; the leases and royalties have been arranged and the title is secure. When it is decided to start drilling, roads are built, water lines laid, and the lumber, casing machinery and other equipment are hauled to the location (often under very primitive and difficult conditions). The apparatus most commonly installed under these circumstances is the Pennsylvania cable system, which consists of a standard derrick or rig, built of wood or steel, about eighty feet in height, having a twenty-foot base and a four-foot top. The strength of the derrick is conditioned entirely by the size and depth of the well the operator wishes to drill, for nowadays nothing is left to chance. The size of the hole necessary in starting a well depends upon the physical formation. If it is soft, it is necessary to start with a hole of large diameter, to overcome the disabilities produced by caving. It sometimes happens that soft formations cave so much that it is necessary to insert several columns of casing before the required depth is reached. A hole with a large diameter is also used in deep drilling.