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Page 139 - From the foregoing statements it may be safely inferred that " the mean height of the barometer at the level of the sea being the same in every part of the globe...
Page 362 - ... moderately concentrated, till the acid is saturated ; then add to it gradually a solution of fixed alkali, commonly called oil of tartar per deliquium. A strong effervescence will ensue, and the iron, instead of falling to the bottom of the vessel, will afterwards rise, so as to cover the sides, forming a multitude of ramifications heaped one upon the other, which will sometimes pass over the edge of the vessel, and extend themselves on the outside with .all the appearance of a plant.
Page 156 - For this purpose, circular and horizontal indentations are cut out quite around it, and at proper distances, according to the thickness to be given to the millstones. Wedges of willow, dried in an oven, are then driven into the indentations, by means of a mallet. When the wedges have sunk to a proper depth, they are moistened, or exposed to the humidity of the night, and next morning the different pieces are found separated from each other. Such is the process which, according to M. de Mairan, is...
Page 124 - Pont-Royal, when at its mean height, is 400 feet broad, and 5 deep. When the river is in this state, the velocity of the water is estimated at 100 feet per minute, taking a mean between the velocity at the surface, and that at the bottom. If the product of 400 feet in breadth, by...
Page 223 - ... a hazel, of different sizes and strength, only they were forked branches, and hazel was preferred, as forking more equally than most other trees ; but it is not requisite that the angle should be of any particular number of degrees. He held the ends of the twigs between each fore finger and thumb, with the vertex pointing downwards. Standing where there was no water, the baguette remained motionless; walking gradually to the spot where the spring was under...
Page 53 - ... will have a very sensible motion; so that the moveable extremity of the small bar cannot pass over the hundredth or thousandth part of a line, without a point of the circumference of the last wheel passing over several inches. If this circumference then have teeth fitted into a pinion, to which an index is...
Page 124 - ... whether the quantity of rain water is sufficient to feed all the springs and rivers, and so far from finding a deficiency, he concludes upon the amount being so great as to render it difficult to conceive how it is expended. According to experiments which have been made, there falls annually upon the surface of the earth about 19 inches of water, but to render his calculation still more convincing, Marriotte supposes only 15, which makes 45 cubic feet per square toise, and 238,050,000 cubic feet...
Page 35 - ... every part of the earth ; the result of which must be a compound tendency passing through the centre, provided the earth be a perfect globe, which we here suppose, on account of the small difference between its figure and that of a sphere. It...
Page 156 - Mairan ; but in our opinion, the answer which he gives to it is very unsatisfactory. It appears to us to be the effect of the attraction by which the water is made to rise in the exceedingly narrow capillary tubes with which the wood is filled Let us suppose the diameter of one of these tubes to be only the hundredth part of a line ; let us suppose also, that the inclination of the sides is one second, and that the force with which the water tends to introduce itself into the tube, is the fourth...
Page 351 - The Philosophical Candle. PROVIDE a bladder, into the orifice of which is inserted a metal tube, some inches in length, that can be adapted to the neck of a bottle, containing the same mixture as in the last experiment. Having suffered the atmospheric air to be expelled from the bottle, by the elastic vapour produced by the solution, apply the orifice of the bladder to the mouth of the bottle...