.0^. \^^ IMAGE EVALUATION TEST TARGET (MT-S) A /^ .5^4fc'. />^. /y ' ^\<^^ ^^ t.y y. u. m 1.0 I.I 1S« ■^ IIIII.2.2 « ... I iy5 ill 11.6 v^ .p /^ // j'> > '/ Hiotographic Sciences Corporation ^ ■1>^ iV 4 # >^ 23 WEST MAIN STREET WEBSTER, N.Y. 14580 (716) 872-4503 12X 16X 20X 24X 28X 32X i ire details las du modifier per une filmage 6es re The copy filmed here has been reproduced thanks to the generosity of: Library of the Public Archives of Canada The images appearing here are the best quality possible considering the condition and legibility of the original copy and in keeping with the filming contract specifications. Original copies ir. printed paper covers are filmed beginning with the front cover and ending on the last page with a printed or illustrated impres- sion, or the back cover when appropriate. All other original copies are filmed beginning on the first page with a printed or illustrated impres- sion, and ending on the last page with a printed or illustrated impression. 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Tous les autres exemplaires originaux sont filmis en commen^ant par la premiere page qui comporte une empreinte d'impression ou d'illustration et en terminant par la dernidre page qui comporte une telle empreinte. Un des symboles suivants apparaTtra sur la dernidre image de cheque microfiche, selon le cas: le symbole — »> signifie "A SUIVRE", le symbols V signifie "FIN ". Les cartes, planches, tableaux, etc., peuvent dtre film6s A des taux de reduction diff^rents. Lorsque le document est trop grand pour dtre reproduit en un seul cliche, il est film6 d partir de I'angle sup^rieur gauche, de gauche d droite. et de haut en bas, en prenant le nombre d'fmages ndcessaire. Les diagrammes suivants illustrent la mithode. / errata id to It ie pelure, pon i n 1 2 3 32X 1 2 3 4 5 6 I I [PRIVATE PRESS.] INSTITUTION OF CIVIL ENGINEERS, MARCH 30, 1858. CHARLES HUTTON GREGORY, Esq., # MEIIBEE OF COUNCIL, IN thp: chatk. The proceedings were commenced by the reading of the following abstract of a l*aper entitled " Observations on the Electrical Qualifications requisite in long Snbpiarino Telegra])h Cables," by Mr. Alfred Varley. The communications lately read, and so fully discussed, on the subject of submarine telegraphy, had suggested the enquiry, whether the cables, as at present constructed, did fulfil, in the best manner, the electrical portion of the problem. It was remarked, that there ai)peared to be some uncertainty, in the minds of those engaged in applying electricity telegraphically, regarding the laws of conduc- tion and induction, and consequently of the nature of the conductor to be employed in long submarine circuits. The conclusions arrived at by the projectors of the Atlantic Cable were referred to, as it was believed that some errors had been inadvertently introduced into their calculations ; but it was trusted that these criticisms would be received in a friendly spirit, as the only desire was to arrive at the truth. The laws of conduction, as ascertained by the Author,, as the result of direct experiments, were — 1st., That a wire one mile long offered half the resistance of one two miles long. 2nd. That two wires, each two miles long, when placed side by side, whicli was Skspion 1K57-58.— No, ^G. (Ill- Miino as niio of (l(»\il>lo the aroa, offcrod (lio samo rosistauci' as one wire one mile loii^. Witli regard to imluction, the results of exi)eriinents tried l)y tlio Author and Mr. C. John Varhy, sliuwed that with flat phites it followed the same law as conduction, de- creasing in regular proportions, as the insulating medium was increased ; thnt was to say, if the inductive force through one plate was twelve, through two plates it would be six, through three plates, four, and so on. Inagntta-porcha covered wire, it probably did not follow j)recisely the same law, as when the insulating materials were j increased in depth, the surface was also enlarged, which partly '* count(;racted the effect of greater thickness. ^\v. C. X. Varley had tried 5f Wr, some experiments which went to show, that in a wire one-tenth of an inch in diameter, coated to the depth of one-tenth of an inch with guttapercha, making a total of three-tenths, when com{)areil with one of the same size, coated to twice that depth, the inductive force of the former was to the latter as 4 to 3-^, or thereabouts, and not 4 to 2: but this result was onlv to be considered as an aj)proximation. j 1"he conclusion arrived at by the projectors of the Atlantic Tele- graph, that in a submarine cable a small wire conducted more rajtidly than a large (me, was thought to be erroneous. If a battery of six cells, with six inches of surface in each cell, was coimected through a circuit of nominally no resistance, a luuch greater cpian- tity of electricity would be found to pass than when convjcted through a long fine wire perfectly insiilated. In a battery with the same number of cells, but with twice the surface, and capable, con- sequently, of giving out twice the quantity, tluough a circuit of nominally no resistance, no more, practically, would be found to be passing, the resistance of the wire measuring out the amount, some- thing in a similar way to water flowing out of a small pipe inserted into the bottom of a cistern. The series might be added to, cell by cell, until, practically, as much was forced through, as the battery originally generated, along a circuit of nominally no resistance. After this had been arrived at, a further addition would not make any perceptible difl'erence, as there was already power enough to force through all that the battery was capable of generating, and from could did tn it had that it ;>pparj I a 1100 US isiilts of showed Lon, tle- ivn was ne plate B plates, (lid not als were li partly lad tried T, ^ •tenth of ' au inch omjjared nductive o\its, and »d as au I itic Tele- bed more a battery ;ounected ,ter quan- conv jcted ' with the able, con- circuit of lund to be lint, some- )e inserted to, cell by lie battery resistance. I not make enough t(t ratini;-, and \ the amount of force given out was nhvays pro})ortionate to the dynamic quantity flowing through the instruments. Intensity was only the medium which forced through this dynamic quantity. The three following conclusions, which had been introduced into previous discussions, were then referred to : — 1st, That a submarine circuit was a Leyden jar, which had to be chargeloycd as one conductor, although there would be only one fourth of the resistance, signals would not i)ass through more quickly than tlirough one, for the inductive surface was also increased four times ; but if these cables were merged into one, whilst the inductive surface would be reduced one-half, the resistance would not bo increased. It was Ijclieved, therefore, that if the iliameter of a conductor was doubled, signals would pass through twice as quickly with the same depth of insuhition. The relations subsisting, telegraphically, between quantity and intensity of electric currents, demonstrated, that if the insulation was imperfect, larger dynamic quantities gave a better chance of working through. Cases had occm-red where increasing the intensity of the battery had produced no perceptible advantage^ whilst increasing the surface in each cell had a very decided elfect. A case was instaixced where, on a leaky circuit of upwards of 212 miles in length, the deflection on the galvanometer had been raised from 23" to 53", by increasing the surface, without adding to the number of cells. The efl'ect of employing batteries of very high intensities for sub- marine wires, with a view to increased rapidity of signalling, was then considered ; and it was stated that, as with high intensities there was greater energy to force through '-^^ stance, the wave of charge would arrive at its maximum more (^ r frontage to a large area of land. The stop-gates at Pond Lane wore constniotcd in order to allow the water to bo drawn off at Uld F«»rd Locks, without incurring the expen.se of a dam. 'J'hcy were 22 feet in width, and tho cill was laid at the level of 7 feet 1 1 inches below the Lee .I'ridge hcadmark. Their construction was very similar to that of the Old Ford Locks, except that the cast-iron pointing cill formed nearly a s(piare nosing to a brick cill, A steam dredging machine was employed for deepening the river, the average cost of raising material being from tenpence to elevenpence per cubic yard, according to the weight, including a "lead" of Ll mile and allowing for wear and tear of machinery. The total cost of the works was about £22,000, which amount included £'1:,000 for land, and £2,000 for plant, now being used on works higher up the river. They were designed and executed by Mr. Beardmore, M. Inst. C.E., assisted by che Author, without the intervention of a contractor. In the second part of the paper, it was argued, that canals were still extensively useful, as a means of conveyance, and that they might be rendered more so, by combination with railways. The returns of the Grand Junction Canal Company, which had to contend with the formidable opposition of the London and North Western Eailway Company, gave an actual increase from 1810 to 18-56, of 202,942 ton.s per annum, or 28 ^ per cent, ; although this was liable to fluctuation from year to year, the average of each quinquennial period, .showed that the increase had been gradual and progressive. This result was in some degree due to a considerable reduction in the tolls, and also to the development of the resources of the 10 ■ i country, due to railways; so tbat canals were now actually profiting by that which in the first instance threatened to annihilate them. The traffic on the River Lee Navigation, which had to compete with the Eastern Counties Railway for its whole length, had steadily in- creased during the years 1 851-6, 25 per cent, in tonnage, and about 50 per cent, in receipts, notwithstanding that the tolls had been considerably raised. As an examplf^ of a different class, namely, of a canal working in conjunction with a railway, the Trent and Mersey system worked by the North Staffordshire Railway Company was cited j and it was stated that, during the ten years from 184G to 185G, the tonnage must have increased 40 per cent. Under this head, the enormous amount of coal distributed by the Regent's Canal, from the Great Northern Railway, was also quoted. It appeared, that in 1 857, the quantity of coal passing upward from the River Thames and Great Northern Railway was 554,788 tons, whilst that passing downwards from the Grand Junction was only 4,997 tons. The former amount included 150,927 tons from the Great Northern Railway. Thus were combined the rapidity of transit of the railway, and the facility of distribution by water communication, by means of the Canal and the Thames. As to the system of management on canals, it was suggested, that interchange of trafiic should be encouraged, by the adoption of a uniform system of tonnage rates per mile ; that there should be unanimity of purpose and cordiality of feeling; that the idea of competition between canals and railways should be abandoned, and that they should mutually assist and be auxiliary to each other, rather than antagonistic, as had too frequently been the case. The extensive establishments at Bull's bridge on the Grand Junction Canal, for the Great Western Railway, and at Maiden-lane on the Regent's Cana\ for the Great Northern Railway, and the arrange- ments of the South Yorkshire Railway and River Dun Company, were quoted. It was also suggested,, that it might be of advantage to the companies to encourage the establishment of manufactories on the canal banks. Stoani tugs were gradually coming into favour for working the 'i hi i i 11 traffic. Tlio difficulty had, hitlicrto, been to use vessels of sulTi- cieut jiower, without injuring the banks. This had, to a certain extent, been overcome on the Regent's Canul, where the tug, con- structed by Mr. Inshaw, of liinniiigham, had a screw on each side, the one being riglit, the other left handed, so that the wash from the one tended to neutralize that from the other. On the Aire and Calder navigation four steam towing barges were employed for the goods traffic, and a diflferent class of towing barge for minerals. Tugs might be employed advantageously on long levels, say of over two miles in length, but where the traffic was large they should not be allowed to pass through the locks, and on shorter lengths horses should continue to be used. Time bills should be adopted, so that steam might be continuously employed. The speed should not exceed from 4 to 5 miles per hour, as at higher rates, the resistance of the water woiUd be so great, as to require an unnecessarily large expenditure of power, and the wave created would tend to destroy the banks. It was specially resolved, that in order to insure a fuller attendance of Members than could be obtained on Easter Tuesday, the meeting should be adjourned until Tuesday evening, April 13th, when it was announced the Monthly Ballot for Members would take place, and the following Paper would be read : " Investigation into the Theory and Practice of Hydraulic Mortar," by Mr. G. Robertson, Assoc. Inst. C. E. Institution of Civil Engineers. — Tuesday, April 13th, at 8 p.m. " Theory and Practice of Hydraulic Mortar ' by Mr. G. Robertson, Assoc. Inst. C. E. .t