A correspondent from St. Pauls, Minnesota, which place is situated on the east bank of the Mississippi about 100 feet above the river, states that the current is very strong there,and he wishes to know what is the best way to obtain a large supply of water by raising it from the river. He enquires if it can be raised by the force of the river operating a spiral current wheel, which might work a pump, or by a hydraulic ram. He tells us that this subject is full ot interest to a great many cities and villages situated on river localities. If the velocity of the current was known, and the nature of the banks of the river above the city for a mile or more known, a i better judgement could be formed of what machine was best adapted to supply the place with water. A hydraulic ram, perhaps, would answer very well; a steam engine we know, would positively answer, but it may be too expensive.