The maximum yield per well is ten barrels per day, and the minimum yield for which it is considered profitable to pump is a quarter of a barrel per day. The yield being in some cases so small, it is usual to pump a number of wells through the agency of one engine, the various pumps being connected with the motor by means of wooden rods. In one instance I saw as many as eighty wells being thus pumped from one center. The motive power was a 70 h.p. engine, which communicated motion, similar to that of the balance wheel of a watch, to a large horizontal wheel. From this wheel six main rod lines radiated, the length of stroke of the main lines being 16 in., and the rate of movement 32 strokes per minute. Some of the wells being pumped from this center were from one-half to three-quarters of a mile distant, and altogether about eight miles of rods were employed in the pumping of the eighty wells. The pipe line system in Canada has not been fully developed, and accordingly the well owner has to convey his oil by road to the nearest receiving station. Thus from the Euphemia oil field the oil has to be "teamed" 17 miles, to Bothwell. For the conveyance of the oil by road a long and slightly conical wooden tank or barrel, resting horizontally on a wagon, is employed. These vessels hold from eight to ten barrels of oil. The Petrolia Crude Oil and Tanking Company is the principal transporting and storing company. The storage charge is one cent (1/2d.) per barrel per month, and the delivery charge two cents per barrel. The petroleum produced in the Oil Springs field is stored separately from that obtained in the Petrolia field. The storage takes place for the most part in large underground tanks excavated in the retentive clay. These remarkable tanks are often as much as 30 ft. in diameter by 60 ft. in depth, and hold from 5,000 to 8,000 barrels. In the construction of the tanks the alluvial soil, of which there is about 18 ft. or 20 ft. above the clay, is curbed with wood and thoroughly puddled with clay. On the completion of the excavation, the entire vertical surface is then lined with rings of pine wood, so that the upper part down to the solid clay is doubly lined. The bottom is not lined. The roof of the tank is of wood, covered with clay. The cost of such a tank is about 22 cents (11d.) per barrel, or 1,760 dols. (L363) for an 8,000 barrel tank, and the time occupied in making such a tank is about six weeks. The crude petroleum from the Petrolia field usually has a specific gravity ranging from 0.859 to 0.877, while the specific gravity of the petroleum from the Oil Springs field ranges from 0.844 to 0.854. The oil occurs in the corniferous limestone, and buildings constructed of this stone frequently exude petroleum in hot weather.