Page:Provincial geographies of India (Volume 4).djvu/88

72 of the creek was covered with large boats, waiting to receive a lading of oil." Long before that date, oil winning was a flourishing industry. In Burmese times, the wells were worked by crude native methods. They were owned by the workers known as twinsas, who were bound to sell the product at a stated price to the king's agent. In the year 1888, scientific methods were introduced by a Company which acquired wells by purchase, obtained concessions from Government, and sank many wells of their own. Since then the industry has very largely developed. Extraction is strictly controlled by Government, and elaborate regulations to ensure safety are enforced. A pipe line conveys the crude oil to Syriam, below Rangoon. In 1921, the output of petroleum from the whole province, principally from Yenangyaung, was 296.09 million gallons.

Gems. The greater part of the world's supply of Rubies comes from the Mogôk mines in Upper Burma. A few rubies, sapphires and spinels have been found at Sagyin near Mandalay, and at Nanyazeik in the Myitkyina district. At Mogôk rubies, many of the coveted pigeon-blood colour, accompanied by large quantities of bright red spinel, a few sapphires and occasionally beautiful blue crystals of apatite, are quarried from a gem-bearing gravel occurring at some depth below the alluvial valley floor. The gems are derived from lenticels of crystalline limestone closely associated with basic igneous rocks bands of which are folded up with the ordinary gneiss. Some think the limestone was derived from certain ingredients of the gneiss and was deposited from percolating solutions some time after the deposition or solidification of the gneisses. Others think that they were ordinary sedimentary limestones laid down upon and subsequently folded up with the gneiss. A few gems have been obtained from the limestone itself by driving cuttings into the hill sides or by excavations in fissures or hollows.

The ruby mines at and near Mogôk, some sixty miles