- Email: [email protected]
Cast iron bridge near constantine, (Algiers.)
Cast Iron Bridge near Conatcmtine, (Algiers.)
163
the wire was liable to start out of the cable after it had been stretched and cut, or softened, owing to the unequal elasticity of copper and gutta-percha, but with Chatterton’s compound considerable force must be used to drag out the copper wire, even when the core has been stretched and is cut open. Table II. shows the strains which various Tvires can support. Table III. gives the dimensions of the cores in some of the most It is noteworthy that 300 miles of the very important cables laid. smallest core practically in use, laid without any outer protection whatever, maintained our connexion with the army for nine months during the Crimean war. (To be continued.)
Cast Iron Bridge near Constantine, (Algiere.) We copy the design of a very graceful cast iron bridge, thrown by a French engineer, M. Martin, over a deep and precipitous ravine, near Constantine, (Algiers.) The span of the main arch is 57.4 metres (188 feet) in span, and the depth from the roadway to the bottom of the ra vine is 120 metres, (393 feet.) The only novelty of any interest about the construction was the method taken to support the centering of the
arch. As the depth was so great, and the bottom occupied by a tora rent liable to sudden and destructive floods, the attempt to build up a support from below would have been both expensive and hazardous. The engineer,. therefore, threw four cables across the chasm, two on
164
Mechanics, Physics, and Chemiatry.
each side of his proposed bridge, from which he supported a platform, on which the arch centering was built. The wooden centres, when finished, found their support at their abutments, and the suspension bridge was retained only for the service of the work, and the iron arch-stones were never permitted to rest upon it.
MECHANICS,
PHYSlCS,
AND
CHEMISTRY.
For the Journal of the Brmklin Institute.
The Working Processeafor the Reduction of the Gray Copper (Tetrahe&de) Ores at Btefanshiitte, in the C’omitat (County) of Zips, in Hungary. By J. L. KLEINSCHMIDT. (Continued from page 132.)
In a second trial, I precipitated, after the separation of the copper by hydrosulphuric acid, oxidation of the fluid, etc., the ferric oxide, partly by carbonate of soda, and then, after filtering, the rest by soda lye. The precipitate thus obtained was melted aith metallic arsenic, cyanide of potassium, and black flux in a crucible, (tute,) but no globule was obtained. Iron and copper were separated in the nitric acid solution by ammonia in the usual way. The ferric oxide was dissolved a second time in hydrochloric acid, and to the solution ammonia added in excess. The copper, by titration in the ammoniacal solution, gave 25.95 per cent. ; add to these 0.98 per cent. from the SbO,, we get 26.93 per cent. of copper. 0*0200 grs. gave 0*0027 grs. ferric oxide, The silver was ascertained by cupelequal to 9-l per cent of iron. Iation. The iron pyrites ores (kiese) which are added to the melting contain lead, but in several experiments I have not succeeded in finding it in the crude speiss, (rohspeise,) but I found it in the slags of the copper refining, (Spleissabziige ;) therefore the lead has a greater affinity to the sulphur, and remains in the ma,tte, and does not go to the speiss. Crude Matte, (RohZech.)-This was digested with nitric acid until all aulphur was dissolved, then dilut.ed with water. The residue, after settling, gathered on a filter, and while yet wet, digested with concentrated muriaticacid, to which, afterwards, water and tartaric acid were added. The residue, which was not dissolved by the muriatic acid, was gathThis, consisting of slag, ered on a filter, and weighed after ignition. was examined before the blow-pipe, by melting with cyanide of potassium, but no reaction of antimony was obtained. The diluted solution was precipitated by hydrosulphuric acid, after it had been warmed to the boiling point with sul hurous acid, in the last det,ermination as tersulphide of antithe precipitate dried, weighe If , and calculated mony. The original solution was measured, and in one portion of it the sulphur determinated by precipitation with chloride of barium, and the preci itate several times boiled with muriatic acid. Iron and copper were g eterminated as mentioned above, the silver by cupellation. C’racde &slag, (Rohdhcke.)-This w&s decomposed by melting with
163
the wire was liable to start out of the cable after it had been stretched and cut, or softened, owing to the unequal elasticity of copper and gutta-percha, but with Chatterton’s compound considerable force must be used to drag out the copper wire, even when the core has been stretched and is cut open. Table II. shows the strains which various Tvires can support. Table III. gives the dimensions of the cores in some of the most It is noteworthy that 300 miles of the very important cables laid. smallest core practically in use, laid without any outer protection whatever, maintained our connexion with the army for nine months during the Crimean war. (To be continued.)
Cast Iron Bridge near Constantine, (Algiere.) We copy the design of a very graceful cast iron bridge, thrown by a French engineer, M. Martin, over a deep and precipitous ravine, near Constantine, (Algiers.) The span of the main arch is 57.4 metres (188 feet) in span, and the depth from the roadway to the bottom of the ra vine is 120 metres, (393 feet.) The only novelty of any interest about the construction was the method taken to support the centering of the
arch. As the depth was so great, and the bottom occupied by a tora rent liable to sudden and destructive floods, the attempt to build up a support from below would have been both expensive and hazardous. The engineer,. therefore, threw four cables across the chasm, two on
164
Mechanics, Physics, and Chemiatry.
each side of his proposed bridge, from which he supported a platform, on which the arch centering was built. The wooden centres, when finished, found their support at their abutments, and the suspension bridge was retained only for the service of the work, and the iron arch-stones were never permitted to rest upon it.
MECHANICS,
PHYSlCS,
AND
CHEMISTRY.
For the Journal of the Brmklin Institute.
The Working Processeafor the Reduction of the Gray Copper (Tetrahe&de) Ores at Btefanshiitte, in the C’omitat (County) of Zips, in Hungary. By J. L. KLEINSCHMIDT. (Continued from page 132.)
In a second trial, I precipitated, after the separation of the copper by hydrosulphuric acid, oxidation of the fluid, etc., the ferric oxide, partly by carbonate of soda, and then, after filtering, the rest by soda lye. The precipitate thus obtained was melted aith metallic arsenic, cyanide of potassium, and black flux in a crucible, (tute,) but no globule was obtained. Iron and copper were separated in the nitric acid solution by ammonia in the usual way. The ferric oxide was dissolved a second time in hydrochloric acid, and to the solution ammonia added in excess. The copper, by titration in the ammoniacal solution, gave 25.95 per cent. ; add to these 0.98 per cent. from the SbO,, we get 26.93 per cent. of copper. 0*0200 grs. gave 0*0027 grs. ferric oxide, The silver was ascertained by cupelequal to 9-l per cent of iron. Iation. The iron pyrites ores (kiese) which are added to the melting contain lead, but in several experiments I have not succeeded in finding it in the crude speiss, (rohspeise,) but I found it in the slags of the copper refining, (Spleissabziige ;) therefore the lead has a greater affinity to the sulphur, and remains in the ma,tte, and does not go to the speiss. Crude Matte, (RohZech.)-This was digested with nitric acid until all aulphur was dissolved, then dilut.ed with water. The residue, after settling, gathered on a filter, and while yet wet, digested with concentrated muriaticacid, to which, afterwards, water and tartaric acid were added. The residue, which was not dissolved by the muriatic acid, was gathThis, consisting of slag, ered on a filter, and weighed after ignition. was examined before the blow-pipe, by melting with cyanide of potassium, but no reaction of antimony was obtained. The diluted solution was precipitated by hydrosulphuric acid, after it had been warmed to the boiling point with sul hurous acid, in the last det,ermination as tersulphide of antithe precipitate dried, weighe If , and calculated mony. The original solution was measured, and in one portion of it the sulphur determinated by precipitation with chloride of barium, and the preci itate several times boiled with muriatic acid. Iron and copper were g eterminated as mentioned above, the silver by cupellation. C’racde &slag, (Rohdhcke.)-This w&s decomposed by melting with