Gill's technological [afterw.] Gill's scientific, technological & microscopic repository; or, Discoveries and improvements in the useful arts, a continuation of his Technical repository, by T. Gill, Volume 1

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Page 297 - ... and heat the whole to ebullition. When the lac is dissolved, cool the solution, and impregnate it with chlorine, till the lac is all precipitated. The precipitate is white, but its colour deepens by washing and consolidation ; dissolved in alcohol, lac bleached by the process above-mentioned yields a varnish, which is as free from colour as any copal varnish.
Page 248 - He saw the steam gun discharge at the rate of from 500 to 1000 balls per minute, and the steam blowing off at the escape valve, during the whole time ; he is equally confident with myself, that the steam may be kept up in such a manner as to discharge a constant stream of balls during the whole day, if required. As regards economy, I am within the truth, when I say, that if the discharges are rapid, one pound of coals will throw as many balls as four pounds of powder.
Page 139 - The village of Mauch Chunk is situated on the western bank of the Lehigh, in a deep romantic ravine, between rocky mountains that rise in some parts precipitously to 800 or 1000 feet above the stream. Space was procured for dwellings by breaking down the adjacent rocks, and by filling a part of the ravine of the Mauch Chunk creek. A portion of this stream has been transferred to an elevated rail-way, and is used to propel a grist mill.
Page 288 - During the display of electric power, so awful to an ordinary observer, the electrician sits quietly in front of the apparatus, conducts the lightning in any required direction, and employs it to fuse wires, decompose fluids, or fire inflammable substances ; and when the effects are too powerful to attend to such experiments securely, he connects the insulated wire with the ground, and transmits the accumulated electricity in silence and with safety.
Page 282 - We will give a preparation which we have always found to succeed, and which, when the operation is performed with the necessary precautions, admits of the finest and most delicate lines being perfectly transferred, without leaving the faintest trace on the paper. For this purpose, it is necessary to take a strong, unsized paper, and to spread over it a size prepared of the following materials : Starch 12O drachms.
Page 142 - Pottsville, situated at the head of the Schuylkill canal, has been the principal source of the supply of anthracite. Many large veins are worked within three miles of the landing ; and some have been opened seven miles to the north-east in the direction of the Lehigh beds.
Page 249 - ... and sir George Cockburn said, that the mischief of it was, it would be to nations what the pistol was to duellists, it would bring all, whether strong or weak, upon a par.
Page 204 - MACHE is a substance made of cuttings of white or brown paper, boiled in water, and beaten in a mortar till they are reduced into a kind of paste, and then boiled with a solution of gum Arabic, or of size, to give tenacity to the paste, which is afterwards formed into different toys, &c., by pressing it into oiled moulds.
Page 299 - Let all the mastic be bruised by a muller on a painter's grinding stone, which will immediately detect the soft or oily tears, which must be rejected; as when dissolved in the mass they prevent the varnish from drying hard, leaving a greasy or tacky surface. The next point of importance is, to procure, if possible, turpentine which has been distilled a second time; but where 2 B...
Page 180 - PAHKINSO.V and FRODSHAM, and which I have frequently transferred from the ship to the shore, for two or three weeks at a time, for the purpose of trial, I have never been able to discover any systematic variations whatever consequent on their removal. With regard to the influence of the iron as a cause of the irregularity, a more decisive evidence of its not being practically discovered under the most favorable circumstances for its exhibition can scarcely be imagined, than took place in the four...

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