Its southern boundaries are more difficultly ascertainable: but, except where they are pressed northwards by the anciently civilized empire of China, these may be assumed at a medium on the thirty-fifth degree of north latitude; from, whence Scythia or Tartary extends in breadth to the extremity of the frozen north.

Such are the extremely various effects which may result to ourselves, and to our customers, from the imposition of taxes on our exports : and the determining circumstances are of a nature so imperfectly ascertainable, that it must be almost impossible to decide with any certainty, even after the tax has been imposed, whether we have been gainers by it or losers.

A.The glass gauges are tubes affixed to the fronts of boilers, by the aid of which the height of the water within the boilers is readily ascertainable, for the water will stand at the same height in the tube as in the boiler, with which there is a communication maintained both at the top and bottom of the tube by suitable stopcocks.