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Gutta percha in photography
206
.Mechanics, .Physics, and Chemist~'y.
strength; and the prepared glass (as soon as the film of collodion has set) is plunged into it. The whole is then placed in its proper position in the camera, the focus having been previously obtained; and the light is thus allowed to act on the prepared film whilst in the bath of nitrate of silver. By this means great cleanliness is preserved in the manipulation, and very delicate pictures are obtained. 1 have used this bath during the whole of the summer and autumn; and several friends, at my suggestion, have adopted it with great success. The bath is made of two pieces of the best plate glass, connected together at the sides and bottom, and gradually.tta)erin,,'~,downwards, so as to form a narrow wedge-shaped bath, the top being about three-e@lths of an inch wide, and the bottom oneeighth. This bath is cemented into a wooden frame, having a closely fitting lid to prevent all dust falling into the solution. 13, l'avisloc/~ St~'eet, Cove~t Garden.
,,~ Simple Process for Peecipilalb~g t]te Cotton contained in Collodion. By ThoMAs CaTT~:.~L, M. D., ~/L J~. C. S. E~g'. ~'c., Braunston. ~ A short time since, I ascertained that on mixing bisulphuret of carbon with collodion~ an immediate precipitation or separation of the cotton takes place, leaving a limpid tluid consisting only of the solvent and precipitant. The cotton presents the same fibrous appearance as though it had not been in a previous state of solution, and as gun-cotton would do if simply immersed in water. When dried (as much moisture as possible being first pressed out between folds of linen or bibulous paper) it cannot be distinguished from the dried pulp of the paper-maker. This singular reaction of the bisulphuret on the collodion, would lead to the suppositim~ that the gun-cotton performs the part of a base to the oxyde of ethyl, (ether,) for this substance is at once deprived of the peculiar properties which it possessed previous to solution. It may serve also to explain more clearly the chemical composition of gun-cotton, or lignine, as acted on by nitric or nitrico-sulphuric acid. Gutta Percha in Photograp/ty. t At the meeting of the Photographic Club on Saturday last, Mr. Fry exhibited some charming pictures on glass, obtained by a combination of gutta pereha and collodion. To the ordinary collodion--gun-cotton dissolved in ether--a small quantity ofgutta pereha is added, which readily dl~soIvcs, rhJs is employed with the ordinary materials for the processes on glass,---the picture being developed by pyro-~allie acid The extraordinary sensibility of this pleparatmn ma3; be referred trom the fact, that a posture copy from a glass negative has been obtained in five seconds by gas-light. The film formed on glass is far more adherent than the ordinary collodion or albumen:--we may~ therefore, expect many valuable results from Mr. Fry's discovery. *From the London ]',aneet for February, 185~. ]" From the London Athonmum, December, 1851.
207 It may interest some of ),our readers to see the following illustration of the remarkable fall of snow mentioned/)y Mr. Birt in the ./1the. nc.~t?z of November the 22d. It occurs in a pamphlet on Meteorology 1)y l?rof. Dove, of Berlin,--in relation to fl~e tbrmation of clouds of snow over plains which are situated at a distance from the cooling summits of m(mntains. He says, that an amateur once gathered together a large assembly in the concert hall of a northern residence. It was one of those i~.)', star-bright nights which arc so aptly called "iron nights" in Sweden. ia the room, howeve.', there was a fearful crowd; and the heat was ~o ,~.','v tlmt several ladies fainted in consequence. An officer ~'ho was t)rcsent sought to end l)~is distressing state of things by attempting to ()pe~a a window,--but this was impossible, so hard was it frozen to the sill. Like a second Alexander, he cut the Gordian knot by breaking a 1):me of glass:--and now, whathappened? It snowedin the room! It is needless to add any comment on this, as the phenomenon explains itself.
T/w Planing of Iro~ and C'asti~ of Glass.'V Messrs. Itawks and Crawshay, of the Gateshead Iron works, have just completed, for Messrs. 1l. W. Swinburne and Co., plate-glass manutactnrers, South Shiek/s, a huge plate of planed cast iron, to be used for the ("L~tin,~, of' glass. [t is, we believe, the largest and heaviest plate of iron that was ever planed. Its dimensions are--length, 18 ft. 4 in.; breadth, 10 ft. 10 in.; depth, 7} in.; and its weight is 26 tons. Mr. Hosking, Messrs. l ~awks and C:awshay's engineer, constructed a planing machine tbr the express purpose of executing the work; and it has the peculiarity --very dangerous in a joke or an argument, but of great "¢alue in a pla~ing,~ ~'aachine--of "cutting both ways." A smooth surface and a dead lc~v~l have been obtained--great merits in a plate for glass casting; for lhe more perfect the level, the less the labor that is required, and the (trudger that is incurred, in communicating an even and polished surface to the glass. A smaller plate, \~'eighing 20 tons, (also intended for Messrs.' ~';winburne's works,) will shortly be placed in the machine.--Gateshead
O~';se.rver. Corzdsh En~nes.$ The number of Pumping Engines reported for-September, is '21; consumption of coal, 1512 ions; water raised, 13,000,000 tons, 10 ihthoms high. The average duty of the whole is, theretbre, 50,000,000 lbs., lifted one foot high, by the consumption of 94 lbs. of coal. October, is 20; consumption of coal 1960 tons; water raised, 16,000~000 tons, 10 fathoms high. Average duty, 49,000,000 lbs., lifted one "foot high, by 94 lbs. of coal. November, is 21; consumption of coal, 1525 tons; water raised, 13,ooo,o00 tons, I0 fathoms high. Average duty~ 49,000~000 lbs., by 94 lbs. eoal.--Lean's Nng@e Beporler. * From the London Athenmum, Deecml)cr, 1851. t From the London Mining Register, tbr December, I85I, ~:Fr~)m Hercpath's Railway Journal.
.Mechanics, .Physics, and Chemist~'y.
strength; and the prepared glass (as soon as the film of collodion has set) is plunged into it. The whole is then placed in its proper position in the camera, the focus having been previously obtained; and the light is thus allowed to act on the prepared film whilst in the bath of nitrate of silver. By this means great cleanliness is preserved in the manipulation, and very delicate pictures are obtained. 1 have used this bath during the whole of the summer and autumn; and several friends, at my suggestion, have adopted it with great success. The bath is made of two pieces of the best plate glass, connected together at the sides and bottom, and gradually.tta)erin,,'~,downwards, so as to form a narrow wedge-shaped bath, the top being about three-e@lths of an inch wide, and the bottom oneeighth. This bath is cemented into a wooden frame, having a closely fitting lid to prevent all dust falling into the solution. 13, l'avisloc/~ St~'eet, Cove~t Garden.
,,~ Simple Process for Peecipilalb~g t]te Cotton contained in Collodion. By ThoMAs CaTT~:.~L, M. D., ~/L J~. C. S. E~g'. ~'c., Braunston. ~ A short time since, I ascertained that on mixing bisulphuret of carbon with collodion~ an immediate precipitation or separation of the cotton takes place, leaving a limpid tluid consisting only of the solvent and precipitant. The cotton presents the same fibrous appearance as though it had not been in a previous state of solution, and as gun-cotton would do if simply immersed in water. When dried (as much moisture as possible being first pressed out between folds of linen or bibulous paper) it cannot be distinguished from the dried pulp of the paper-maker. This singular reaction of the bisulphuret on the collodion, would lead to the suppositim~ that the gun-cotton performs the part of a base to the oxyde of ethyl, (ether,) for this substance is at once deprived of the peculiar properties which it possessed previous to solution. It may serve also to explain more clearly the chemical composition of gun-cotton, or lignine, as acted on by nitric or nitrico-sulphuric acid. Gutta Percha in Photograp/ty. t At the meeting of the Photographic Club on Saturday last, Mr. Fry exhibited some charming pictures on glass, obtained by a combination of gutta pereha and collodion. To the ordinary collodion--gun-cotton dissolved in ether--a small quantity ofgutta pereha is added, which readily dl~soIvcs, rhJs is employed with the ordinary materials for the processes on glass,---the picture being developed by pyro-~allie acid The extraordinary sensibility of this pleparatmn ma3; be referred trom the fact, that a posture copy from a glass negative has been obtained in five seconds by gas-light. The film formed on glass is far more adherent than the ordinary collodion or albumen:--we may~ therefore, expect many valuable results from Mr. Fry's discovery. *From the London ]',aneet for February, 185~. ]" From the London Athonmum, December, 1851.
207 It may interest some of ),our readers to see the following illustration of the remarkable fall of snow mentioned/)y Mr. Birt in the ./1the. nc.~t?z of November the 22d. It occurs in a pamphlet on Meteorology 1)y l?rof. Dove, of Berlin,--in relation to fl~e tbrmation of clouds of snow over plains which are situated at a distance from the cooling summits of m(mntains. He says, that an amateur once gathered together a large assembly in the concert hall of a northern residence. It was one of those i~.)', star-bright nights which arc so aptly called "iron nights" in Sweden. ia the room, howeve.', there was a fearful crowd; and the heat was ~o ,~.','v tlmt several ladies fainted in consequence. An officer ~'ho was t)rcsent sought to end l)~is distressing state of things by attempting to ()pe~a a window,--but this was impossible, so hard was it frozen to the sill. Like a second Alexander, he cut the Gordian knot by breaking a 1):me of glass:--and now, whathappened? It snowedin the room! It is needless to add any comment on this, as the phenomenon explains itself.
T/w Planing of Iro~ and C'asti~ of Glass.'V Messrs. Itawks and Crawshay, of the Gateshead Iron works, have just completed, for Messrs. 1l. W. Swinburne and Co., plate-glass manutactnrers, South Shiek/s, a huge plate of planed cast iron, to be used for the ("L~tin,~, of' glass. [t is, we believe, the largest and heaviest plate of iron that was ever planed. Its dimensions are--length, 18 ft. 4 in.; breadth, 10 ft. 10 in.; depth, 7} in.; and its weight is 26 tons. Mr. Hosking, Messrs. l ~awks and C:awshay's engineer, constructed a planing machine tbr the express purpose of executing the work; and it has the peculiarity --very dangerous in a joke or an argument, but of great "¢alue in a pla~ing,~ ~'aachine--of "cutting both ways." A smooth surface and a dead lc~v~l have been obtained--great merits in a plate for glass casting; for lhe more perfect the level, the less the labor that is required, and the (trudger that is incurred, in communicating an even and polished surface to the glass. A smaller plate, \~'eighing 20 tons, (also intended for Messrs.' ~';winburne's works,) will shortly be placed in the machine.--Gateshead
O~';se.rver. Corzdsh En~nes.$ The number of Pumping Engines reported for-September, is '21; consumption of coal, 1512 ions; water raised, 13,000,000 tons, 10 ihthoms high. The average duty of the whole is, theretbre, 50,000,000 lbs., lifted one foot high, by the consumption of 94 lbs. of coal. October, is 20; consumption of coal 1960 tons; water raised, 16,000~000 tons, 10 fathoms high. Average duty, 49,000,000 lbs., lifted one "foot high, by 94 lbs. of coal. November, is 21; consumption of coal, 1525 tons; water raised, 13,ooo,o00 tons, I0 fathoms high. Average duty~ 49,000~000 lbs., by 94 lbs. eoal.--Lean's Nng@e Beporler. * From the London Athenmum, Deecml)cr, 1851. t From the London Mining Register, tbr December, I85I, ~:Fr~)m Hercpath's Railway Journal.