8 



HYDROSTATICS. 



with water ; but quicksilver may be 

 employed instead of water, and as it 

 is between thirteen and fourteen times 

 heavier, we shall have a power of ten 

 tons, by the use of a tube and a few 

 pounds of mercury ; and in like manner 

 the power of a ton weight may be 

 obtained within the space of a square 

 foot in breadth, by a tube a little less 

 than three feet long, and of the bore of 

 a common goose quill. 



The instrument, or rather plaything, 

 called the Hydrostatic Bellows, is con- 

 structed upon the same principle. It 

 consists of two boards attached to one 

 another by leather, going all round 

 them, and making the space within 

 water-tight ; there is no valve as in 

 the air-bellows, but instead of it, a 

 hole is bored in the upper board, 

 and a pipe inserted, through which 

 water is poured so as to fill the 

 space between the boards. If the 

 boards be a foot and a half long, and 

 sixteen inches broad, and you load the 

 upper one with three hundred weight, 

 a quarter of a pound of water poured 

 through the tube, and rising only three 

 feet in it, will raise the whole weight 

 as high as the leather allows. In 

 this way it will raise two stout men ; 

 and if, instead of pouring water into 

 the pipe, the two men stand upon the 

 upper board, and one of them blows 

 into the pipe, the pressure thus made 

 upon the water being conveyed in every 

 direction, will produce the same effect, 

 and raise them both. The smaller the 

 bore of the pipe, the easier will they 

 be raised, and by stopping it with the 

 finger immediately after blowing, so as 

 to keep in the air, they may keep them- 

 selves raised up. So when water is 

 poured in, if the pipe be ever so small, 

 and contain ever so little water, pro- 

 vided it be long enough, the weight 

 will be raised by it. 



A more striking as well as accurate 

 manner of exhibiting this experiment was 

 contrived by Ferguson, a man of great 

 genius, who from the humble condition 

 of a shepherd's boy raised himself to 

 rank with the most useful philosophers 

 of his age, and composed a work upon 

 the different branches of Natural Phi- 

 losophy that still holds a high place 

 among the books which treat of those 

 sciences, although he never had any 

 further education from teachers than 

 three months' reading and writing. A 

 tube A B * (fig. 9.) is fixed upright in the 



L * As the tube A B could not hare sufficient length 



end of a box C D E F, open at the top 

 and on one side. The tube is bent at B, 



fin- 9 



and inserted in the neck of a bladder L, 

 upon which is laid a board O P, and 

 upon the board different weights m n, 

 through a hole in each of which the 

 pin I K, fixed in the board, passes ; an 

 arm G I, passes from the box to steady 

 the pin ; water is then poured through 

 A B till it fills the bladder, and the 

 bladder is stretched, and raises the 

 board, as soon as the water rises in 

 the tube, although the weights may be 

 above sixteen pounds, and the water in 

 the tube not a quarter of an 'ounce. 



The uses to which this power may 

 be applied are of great variety and 

 extent ; and this branch of art appears 

 as yet to be in its infancy. There has, 

 however, been a most valuable and 

 ingenious application of it by the late 

 Mr. Bramah, in what is called the Hy- 

 drostatic Press, by which a prodigious 

 force is obtained, strictly upon this 

 principle, with the greatest ease, and 

 within a very small compass ; so that a 

 man shall, with a machine the size of a 

 common teapot, standing before him 

 on the table, cut through a thick bar 

 of iron as easily as he could clip a 

 piece of pasteboard with a pair of shears. 

 The machine is thus constructed. E F 

 {fig. 10.) is a solid mass of wood or 

 masonry, rendered steady by its weight, 

 or by being fixed in the ground. B 

 represents a strong horizontal board, 

 moveable up and down in grooves of the 

 two uprights ; and any substance to be 

 pressed or broken, is placed in the 

 space above it. The piston A, on 

 which B rests, moves up and down in 

 the hollow cylinder L, and fits the neck 

 N, so as to be water-tight. From the 

 cylinder runs a tube, of much less bore 



without encroaching too much upon the page, it is 

 represented as if a part of it betwixt the extremites 

 had been removed. 



