In various parts of the world there are springs, or natural sources, of inflammable oil. Some of these have been known for thousands of years, but most of them are of recent discovery. The oil which flows from these springs is generally known as “petroleum,” the word being of Latin origin, and signifying rock oil. The most productive oil springs are of artificial origin, and are made by boring into the earth, or rock, in certain localities. The most famous natural deposit of this substance, or anything akin to it, on the surface of the earth, is in the Island of Trinidad, in the West Indies, where it forms a lake of asphaltum and petroleum, which is called Tar Lake. This material is a very good substitute for pitch, and is extensively used for coating vessels, and preserving their timber. A gentleman who has visited this lake says that it is about a mile from the sea-shore, and the distance around it is about a mile and a half. Near the shore the tar is solid, and appears as if it had cooled, when the liquid was boiling, in large bubbles. As one goes from the shore to the middle of the lake, the temperature increases, the matter becomes softer, and in the centre it boils steadily. At a distance, when first seen, it resembles a lake of water; but when one approaches it, it appears like glass. A strong odor of sulphur arises from it, and can be detected at a distance of eight or ten miles. There is a bed of coal under the lake. It is of bituminous character, and makes a thick smoke when burning. [Sidenote: THE SACRED FIRE WELLS.] The largest supplies of petroleum are obtained in America. Throughout Europe and Asia there are many petroleum wells. One of the most celebrated localities where they are found is the eastern shore of the Caspian Sea. At Baku, on the shores of the Caspian, there are many springs of naphtha and petroleum, and a great many streams of inflammable gases. The abundance of these wells caused the region to be called The Field of Fire; and in the ancient times Baku was known as the Sacred City of the Fire Worshippers. The annual value of this production is about half a million of dollars. About fifteen miles from Baku there is a jet of inflammable gas rising from the rock, and known as the Perpetual Fire. A temple has been built over it, and the fire has been burning for hundreds of years. Pilgrims come from all parts of Asia to visit this sacred well. The place is in charge of a large priesthood, who are supported by the gifts of the devotees. Another region, quite as wonderful as that of Baku, is the Rangoon district, in India; and a considerable portion of India has been, for thousands of years, supplied by it with rock oil. One authority says, that the number of wells in that district is nearly six hundred, yielding half a million hogsheads of oil annually. Most of the Rangoon wells are artificial, and are sunk in beds of sandy clay, resting on the sandstone, but the wells rarely exceed a hundred feet in depth.