There is, however, in reality, be it distinctly understood, no power absolutely gained; but the man’s force is _concentrated_, as for instance in compressing the bale of cotton, to an extent which, if the ordinary mechanical powers of the lever or screw were employed, would require the aid of ponderous machinery. Mr Bramah was therefore greatly mistaken when he published it as the discovery of a new mechanical power: but he invented a beautiful and most effective means of simply accumulating a prodigious force by the very simple means of the hydrostatic pressure of fluids. Hydraulic or Bramah presses are applied in New York and other American ports for the purpose of raising large vessels on strong wooden platforms out of the water, for effecting repairs, &c. They are also employed in removing houses--some of them brick, and three stories high--from one part of a street to another. In this case strong wooden beams, like the ways used in ship-launching, are placed under the house, and in the direction of the intended site, and hydraulic presses are then employed for pushing the house along, with prodigious force, and so gradually and gently as not even to crack the plaster of a room ceiling. By the same means the roof of a large cotton factory near Aberdeen was raised _entire_, and an additional story added to the building, without displacing a single slate! In this instance the roof was lifted gradually about four inches at a time, progressing from end to end of the building, the height of the walls being increased by a single row of bricks at a time. Such are a few of the results of a single principle, a rule to which there is no exception, which holds equally good in the organic as in the inorganic world. Even the blood-vessels of the body are subject to this law--the sides of all vessels below the level of the heart enduring an additional outward pressure of half an ounce for every inch in height, which at the toes would amount to somewhere about two pounds. When a person stands erect in a bath, the pressure on all parts of the body is not equal; it is greater upon the legs than upon the trunk; the former are pressed upward, and hence in part the difficulty experienced in standing upon the bottom in deep water. T. A. * * * * *