Recent Improvements in Arts, Manufactures, and Mines: Being a Supplement to His Dictionary

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D. Appleton, 1845 - Industrial arts - 304 pages
 

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Page 81 - It occurred to me, therefore, that if the surface of the plate were engraved, an impression might be obtained. This was found to be the case ; for on detaching the precipitated metal, the most delicate and superficial markings, from the fine particles of powder used in polishing, to the deeper touches of a needle or graver, exhibited their correspondent impressions in relief with great fidelity. It is, therefore, evident that this principle will admit of improvement, and that casts and moulds may...
Page 161 - I introduce a current of steam by a pipe, so that it passes through the perforated plate and the madder which is upon it. During this process, which occupies from one to two hours, a substance is produced of a dark brown colour approaching to a black.
Page 62 - The drum itself consists of 2 semi-cylinders; the under of which is made fast to a strong iron framing, and the upper is hinged to the under one behind, but bolted to it before, so as to form a cover...
Page 61 - ... in a thin layer, for a few days, or by boiling, for a few minutes, with a little water, 20 per cent, of solid caoutchouc. The latter, though it has the consistence of pretty rich cream, has a specific gravity of only 1,0175.
Page 65 - This phenomenon is akin to that exhibited in the process of wire-drawing, where the iron or brass gets condensed, hard, and brittle ; while it disengages much heat; which the caoutchouc thread also does in a degree intolerable to unpractised fingers, as I have experienced. Having been favoured by Mr. Sievier, managing director of the Joint-stock Caoutchouc Company, and by Mr.
Page 295 - The substance to be examined is weighed and put into the flask A, into which water is then poured to the extent of one-third of its capacity. B, is filled with common English sulphuric acid to about half its capacity. Both flasks are then corked (by which they become united by the rectangular tube), and the apparatus is weighed.
Page 62 - ... inches to withstand every strain produced by the fixed teeth holding the caoutchouc against the revolving arms. Five pounds constitute a charge of the material. One of the most remarkable phenomena of the kneading operation, is the prodigious heat disengaged in the alternate condensation and expansion of the caoutchouc. Though the water be cold as it trickles in, it soon becomes boiling hot, and emits copious vapours.
Page 40 - Paris is paved, was not at all im • paired, and would, apparently, have resisted any degree of cold ; while that in some parts of the Boulevard, which was composed of vegetable tar, cracked and opened in white fissures. The French Government, instructed by these experiments, has required, when any of the vegetable bitumens are laid, that the pavement should be an inch and a quarter thick ; whereas, where the bitumen composed of mineral tar is used, a thickness of three quarters of an inch is deemed...
Page 161 - I place a quantity of stones, or gravel, and over the stones, or gravel, common wrappering, such as is used for sacks. Below the bricks is a drain to take off the water which passes through the filter. In a tub adjoining the filter is kept a quantity of dilute sulphuric acid, of about the specific gravity of 105, water being 100.
Page 294 - ... for tartaric acid, 28 grains : then in each case we shall obtain a volume of carbonic acid gas proportioned to the strength and purity of these acids respectively. The nitric, hydrochloric, and acetic acids are referred to in their anhydrous state ; the tartaric and citric in their crystalline. If the latter two acids be pure, a solution of...

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