531 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



LOCTOBEB, 



Lord F. Fitzrlaronce; as also xvas Mr. Wrifjht, C.E., who con- 

 ilucted the operations at tlie hlastinp of Rouii<l(lown Cliff, near 

 Dover; and Colonel Sandham, Sir II. Shiffiior, and other gentlemen 

 of eminence. 



SMOKY CHIMNEYS. 



-If the following mode was adopted in building our fire- 

 place openings and flues, we should re- 

 I I quire a much less nuinlier of those in- 

 I I confrruous inventions at the tops of 

 j I our chimneys, disfiguring? as they do tlie 

 / ) sky-line of our houses It has been 

 / / successfully adopted hy Mr. Pierce, of 

 / / Jermyn-street, and ought to be gene- 



/ /' rally known. 



llis plan is to fill-in the openings of 

 old chimneys, and in building new ones, 

 to contract them quickly though gra- 

 dually, by means of a cmrfx gulheriiig, 

 in contradistinction to the coiicnre, which 

 was formerly much in use. (It forms a 

 quicker draft, and is not a receptacle 

 for cold air, as the latter is.) I have 

 tried it, and think it due to Mr. Pierce 

 to say that it has fully answered. The 

 diagram will illustrate it practically. 

 The more perpendicular and central 

 tlie flue is carried up for the first two or 

 three feet before gatliering over on 

 either side, the more efficient will it be 

 found. Let all bends be very easy, the 

 flue of uniform size, with sound con- 

 struction, and the fire-place tqienings 

 proportionate to the size of tlie rooms. 



I should observe that, gatliering the 



flues over all in one direction, without 



returning them in an other, is now exploded. It is found to be 



quite immaterial as to where the flues go, provided all bends are 



easy. 



John Bubges Watson. 

 39, Matichcstcr-i-lrfet, Manchester-square. 

 Hept, 217/1. lis JO. 



y 



I I 



I 



BUILDING BRIDGES IN THE AIR. 



The Academy of Sciences has at present under consideration a 

 plan of a most extraordinary character, being neither more nor 

 less than a suspension bridge between France and England. 

 M. Ferdinand Lemaitre proposes to establish an aerostatic bridge 

 between Calais and Dover. For this purpose he would construct 

 strong abutments, to which the platform would be attached. At 

 a distance of 100 yards from the coast, and at distances of 

 every 100 yards across the Channel, he would sink four 

 barges, heavily laden, to which would be fixed a double iron chain, 

 of peculiar construction. A formidable apparatus of balloons of 

 ail elli]itical form, and firmly secured, would support in the air the 

 extremity of these chains, 'which would be strongly fastened to 

 the abutments on the shore by other chains. Each section of 100 

 yiirds would cost about 300,0obf., which would make 84,000,000 for 

 the whole distance across. These chains, supported in the air at 

 stated distances, would become the point of supiiort to this fairy 

 bridge, on which the inventor proposes to establish an atmospheric 

 railway. This project has been developed at great length by Die 

 inventor. 



Rhine Bkidgb. — It appears from an olTicial document published 

 by Mr. V.in der Heidt, the Minister of Trade and Public \Yorks, 

 that the committee ajipoiiitcd to examine the merits (if the various 

 plans for a bridge over the Khine, between tlie cities of Cologne 

 and Deutz, have awarded the first jirize of 2.50 frederics d'or to 

 Mr. John W. Schwedler, architect, of L!erlin, and the second prize 

 of 125 ftederics d'or to Captain Scartli William .Moor^om, of lion- 

 don, the engineer. There were several English competitors, 

 among others .Mr. Fairbairn. 



ON GALVANIC SOLDERING. 



I.v the 'Technologist' M. Eisner gives an account of some expe- 

 riments he has made on galvanic soldering. Under the name of 

 galvanic soldering, a process is known by means of which two 

 pieces of metal ma-y be united by means of another metal, which 

 is preci|>itated thereon through the agency of a galvanic current. 

 This mode of soldering by the '-wet method" has been often 

 recommended in various periodicals relating to the industrial arts; 

 but it has been objected that— practically speaking — the union 

 between two pieces of metal could not be effected by means of a 

 metal so precipitated by galvanic agency. In order, however, to 

 arrive at a definite conclusion upon this question, M. Eisner under- 

 took thefollow ing experiments, making use of a Daniell's "constant 

 battery." The first experiment he made was by placing upon the 

 end of the copper wire, which formed the negative electrode, a 

 strong ring of sheet copper, cut asunder at one point, the distance 

 between the severed parts being about one-half cr one-third of a 

 millemetre, and immersing it in a bath of sulphate of copper. At 

 the end of a few days (during which time the exciting liquors were 

 several times renewed) the space in the severed portion of the ring 

 was completely filled up with copper regulus, which had been pre- 

 cipitated; and on partially cutting with a file through the part 

 thus filled up, and examining it with a lens, it was observed to be 

 very equally filled with solid and coherent copper. A second 

 experiment was made with another copper ring cut into two parts, 

 and the two segments placed with the faces of the sections opposite 

 each other, and similarly submitted to the action of a galvanic 

 current. At the end of a few days the segments were united by 

 the copper precipitated, and again formed a complete ring. A 

 third experiment was made by placing two strong rings of sheet- 

 copper, with their freshly-cut faces upon one another, so that the 

 two rings constituted a cylinder. These rings were surrounded by 

 a band of sheet-tin, coated with a solution of wax, so that the two 

 rings were equally surrounded by a conducting material. The 

 rings were then attached to the negative wire of the batterv. and 

 immersed in a bath of suljihate of copper. At the end of a few 

 days the interior surface and the contact surfaces of the two rings 

 were covered witli precijiitated copper. The rings were only 

 submitted to the galvanic current to such an extent as to cover 

 their interior surface with a thin coating of precipitated copper, 

 and yet they were so completely re-united that they formed a 

 single cylinder. The exterior conducting covering of tin was, of 

 course, removed, before testing the cohesion of the galvanic 

 precipitate. 



From these experiments, there appears to be no doubt that two 

 pieces of metal may be firmly united or soldered liy galvanic agency. 

 It will, therefore, be possible to firmly unite the different parts of 

 a large piece of metal, and to make a perfect figure of them by 

 galvanic precipitation of a metal (copper in ordinary cases.) If 

 solutions of salts of gold or silver were employed in as concentrated 

 a form as those of copper above-mentioned, there is reason to 

 believe that galvanic soldering would also result. In fact, M. de 

 Ilackewitz states, that in some experiments on a larger scale, 

 which he undertook, to obtain hollow figures by galvano-plastic 

 means, he had remarked that galvanic union often took place 

 between the pieces operated upon. M. Eisner states, that while 

 conducting the experiments above-mentioned, he remarked that, 

 liy employing too powerful a current, the negative electrodes of 

 copper, and even the plate of copper, and ring of the same metal 

 resting thereon, became covered with a deep brown substance, in 

 the same manner as this occurs under similar circumstances in 

 galvanic gilding, as is well known. After several unsuccessful 

 attempts to prevent the formation of this brown coating, M.Eisner 

 found that it was possible to remove it entirely on immersing the 

 articles covered therewith, during a few seconds, in a mixture of 

 sulphuric and nitric acids. By this means the precipitated cojiper 

 vvas made to assume its natural red colour. 



M'ith respect to the cohesion of the galvanic soldering, it is the 

 same as that of copper or other metal precipitated by iralvanic 

 agency. It w ill, moreover, be well understood, that too energetic 

 galvanic excitation must have an injurious influence upon the 

 cohesion of the metal precipitated; and in this case precisely the 

 same phenomena will be oliserved as those which have long 

 manifested themselves in ordinary galvano-plastic operations. 



