35,000 5 £50,000 Stk 41% 50,000 10 5 £300,000 100 4% 7,500 10 37,350 12 12/£150,000 100 4% III. -ELECTRIC TRACTION. Do. 44% Cum. Pref... Do. 4% Mt. Deb. Stk. Red. 100 51 101-104 101-103 155,000 £116,000 £120,000 28- 27 60,000 86 88* 11 50,987 30,000 93 96 72 75* £150,000 Stk 4% 125.000 10 £50,000 314,016 500,000 £350,000 50,000! 110,923 34-4 88-91* Do. 6% Pref... Isle of Thanet Elec. Trams. and Do. 4% 1st Mort. Deb. Stk. Red. 100 Madras Electric Trams (1904), Ltd., 5% Deb. Stock, Red. Metropolitan Elec.Trams, Ltd., Def. 5% Cum. Pref... Do. Do. 41% Deb. Stock, Red. 100 6 New General Traction Co., Ltd., 6% Cum. Pref. 2/98 North Metropolitan Tramways Co.. 34% Do. 34% Mort. Debs. 100 5% Perth Electric Trams, Ltd. (W.A.) 5% 1st Mort. Deb. Stock, Red.. 100 Potteries Elec.Traction Co., Ld.,Or. 5% Cum. Pref. Do. Do. 44% Deb.Stk., Red. 100 102-102 101-103 101-103 TE IV.—ELECTRIC LIGHTING AND POWER. Paid up. Closing Prices. 104 105 140-145 101-104 16 1 6% Cum. Second Pf. Do. 7% Cum. Pref. Shares.. do. 44% Cum. Pref.. do. do. (1903) Chelsea Elec. Sply. Co., Ltd., Ord. Do. do. 41% Deb. Stk., Red 100 5/- City of London EI.Lghtg.Co., Ld.,O. Do. 6% Cum. Pref. Do. 5% Deb. Stk., Red 107-109 103-111 13-14 100 121 -125 Do. 44% 2nd Deb. Stk., Red 100 County of London Elec. Supply Co., 10 100 5 100 11-12 |102 —104* 51-51 101-104 5 10 11 5 101 5 78 102 Ltd., Ord. 2 93 41 94-98* 6% Cum. Pref. Do. 41% Deb. Stk., Red. 44% 1102 Do. 2nd Deb. Stk., Prv. Crts. all paid, Red 100 4/6 Edmundson's Elec. Cor. Ltd., Ord. Do. 44% 1st Mort.Db.Stk.Reg 100 ing Corp, Ltd., 6% Cum. Pref. provision made for passing in and out by the aid of motor capstans and kindred appliances. On completion the barrage would hold up a volume of fresh water from Gravesend to Teddington equal to 4,860 million cubic feet. The daily flow over the weir at Teddington, i.e., the average total daily supply of fresh water, exclusive of the water taken by the London Water Companies, amounts to 113,000,000 cubic feet, independent of the additional affluents from the River Lea and Essex streams, of streams on the south bank, and of sewage effluents from Barking and Crossness and storm overflows. Taking everything into consideration the total is 202,000,000 cubic feet, and taking the value of the river at 4,860,000,000 cubic feet, the daily discharge will at least be about one twenty-fourth with a steady downward flow of about a mile to a mile-and-a-half per hour always running seaward. COST OF CONSTRUCTION. The cost of construction of the barrage, tunnel and auxiliary works is estimated at £4,100,360, and the time required for completion, three years, so that having regard to the magnitude of the work, the amount is not unreasonable in comparison with the purchase of docks, creating new ones, dredging extending over ten years in the river, at a proposed combined outlay of £37,000,000. In connection with the dredging scheme, it must be borne in mind that there is a probability of the wharves giving way, as recently occurred at Barking, and at the Port of Boulogne. At the latter place the dredging undertaken with the view of enabling the cross Channel steamers from Folkestone to get in at low water has caused several hundred yards of quay to sink some feet, and the masonry to crack through from top to bottom. The French engineers are excavating behind the masonry in the hope of getting a new foundation, but it means great expense. The possibilities of the barrage as a storage reservoir of fresh water must not be lost sight of. It will contain nearly a year's supply, even at the estimated requirements of 1941, and the fact that the new storage reservoirs constructed at Staines and other places are nearly all by some oversight built outside the line of fortifications for the defence of London, gives additional value to the barrage scheme. It is only during the months of August and September, as a rule, and then for a short period, that the supply, including the water drawn by the companies, is below the 66,000,000 cubic feet passing over the weir daily, but as the Thames and Severn canal has been opened for through traffic recently, after being practically derelict for years, the author points out that it would not be a difficult feat of engineering to tap the Severn River, and thus have an additional supply, that so far as London is concerned would settle the water question without going to Wales or some other source at an estimated cost of £24,000,000 as proposed by the London County Council. When the river is held up by the barrage, the present unsightly mud banks will be covered, and it will be possible to develop the large areas of sloblands lying idle on both sides of the river below the levels of Trinity highwater mark, between Woolwich and Gravesend. The barrage will prevent flooding from the sea; pumping arrangements are now being installed by the London County Council on both sides of the river, for draining and preventing overflow. A DEEP WATER CHANNEL TO THE NORE. Below Gravesend it is necessary that a channel of 30 ft. to 32 ft. in depth at low water Spring tides should be obtained to the Nore. At present vessels drawing from 24 ft. to 25 ft. cannot get to Gravesend through the present channel at low water without running the risk of grounding. Consequently they prefer to anchor and come up with the rising tide. At Gravesend there is 40 ft. to 45 ft. at low water, and at the Ooze deep (to the east of the Nore Lightship) there is 50 ft. at low water. Thus it would not be a difficult matter to secure by mechanical means a through channel waterway. But to place training walls on the north side from Canvey Island would, as suggested by the 1894 commission, be a great mistake, because there exist in this district, within an area of a few miles, some important factors that regulate the ebb and flow of the tides. On the north side there is Canvey Island, with its creeks; on the south side the Isle of Grain, with its creeks, and the mouth of the River Medway. At the Nore the ebb tide coming down from Gravesend is about spent, and the sand and mud in suspension are deposited; the same may be said with regard to the creeks, and finally with regard to the Medway. Thus there is a confluence of tides and cross-currents at the Nore, all enfeebled, and consequently sandbanks occur. In the estuary the entrance to the Swin Channel, too narrow at present, has, owing to its proximity to the shore, the upper current running in an opposite direction to the lower one, so that vessels in ballast using this Channel to and from the north do not answer their helm, and consequently there are more collisions and wrecks in this channel than in all the others. Therefore the Barrow Channel, which is both wide and deep, should be utilised. As to the suggestion that a direct straight channel might be made from the Nore to the Alexandra Channel, it could certainly be done, but, as to maintaining it, the author has great doubts, and therefore agrees that the Edinburgh Channel, although some miles longer, is safer, and not so liable to silt up, being protected from the North Sea by the Long Sand. The volume of the water in the estuary is computed to be at high Spring tides 70,200,000,000 cubic ft., and at low water 30,500,000,000 cubic ft. What is known as the tidal wave arises from the heaping up of the waters, and as the wave approaches the indented coast line its process is stopped, and the water being confined in the narrow channels fills up the estuaries and creeks, and in those cases the tide is higher than the open seas. In shallow water such as the North Sea and Channel, the tides seldom exceed 15 ft. rise, and 15 ft. Spring tide at the Nore. THE CHARLES RIVER BARRAGE. The United States Government have for some years past contemplated putting a barrage across the Charles River at Boston, which river is similar in many respects with the Thames, but not so large in volume. After most searching inquiry from an engineering and sanitary point of view, they have now decided to erect the barrage, and commenced operations in June last. A special report has been published and issued, which will be found most interesting and instructive. The adoption of the Thames barrage, as a whole, deserves, in the opinion of the author, the most careful and serious consideration of the naval and military authorities. Commerce," and Heat Treatment Experiments with Chrome Vanadium Steel." Captain Sankey, one of the authors of the latter paper, drew attention to the remarkable properties of chrome vanadium steel, and specially drew attention to the fact that when the material was soaked for three hours at 1,200 deg. Cent., it gave considerably better results than when soaked for twelve hours at the same temperature. Also, in the former case, the structure was not nearly so ruined. Various modifications had been made in Professor Arnold's machine for this case, which modified some of the results. One alteration that had been made was that the stroke had been altered from 1 in. to 2 in. Although these alterations were only small, he pointed out that the results, in order to be comparable with the rest, must multiplied by two, thus bringing the value to approximately 1,600. be The President, in thanking the authors, said he had received a letter from Sir William Roscoe, who regretted his inability to be present at the meeting, as it was a subject in which he had been interested for fifty years. It would be remembered that Sir William Roscoe was one of the first-if not the first-to separate vanadium. Dr. Carpenter pointed out that the National Physical Laboratory determined the recalescence point of this steel by a differential method, and made the average 705 deg. Cent.-1,301 deg. Fah.--with a temperature of maximum intensity of about 740 deg. Cent.--1364 deg. Fah. He thought there might be some doubt as to how these figures were arrived at, and stated that they were obtained from the cooling curve. THE VALUE OF VANADIUM AND CHROMIUM. Professor Harbord referred to the method of making tests in bulk for such materials as rails. This was so expensive that it would be infinitely better if some simple means--as in the case of impact tests--could be adopted, but at present the great objection lay in the irregularity of the results. He would like to ask Mr. Seaton if he obtained the same irregularity. The method adopted by Breuil and Volga was then briefly described, which consisted of clamping one end of the test piece firmly in a vice and allowing a weight to drop on the free end. With regard to the question of notching the bars, he pointed out that Breuil and Volga had come to the conclusion that it was better to leave the bar quite plain, with no notch of any description. He asked Mr. Kent-Smith if he could say how much the vanadium and how much the chromium respectively had to do with the properties of this class of steel, as the data, if it could be given, would be very interesting. Dr. Stanton said that with regard to impact tests he had had samples of steel supplied, and found that one broke after one blow and yet stood a shock of 50 per cent. greater than one that stood forty-three blows. They had been tested under quantities worked out by the "proof resilience" formula, and there was no permanent set. When the load was increased about 25 per cent. greater than that calculated from the equation there was deformation of the bar. Mr. Blount wanted to know if anything could be added to the methods of testing that could tell us what cause there is for disease in steel. He thought Professor Unwin was wrong in assuming that mild steel was a homogeneons material, and considered it more analogous to a muscle, and both the molar and the micro structure-the latter corresponding to the nerves—must be considered. On the question of standardisation of impact tests he was of opinion that very many more experiments must be made before any definite conclusions were arrived at, as at present our knowledge was not sufficient to justify the standardisation of impact tests. THE MAITLAND EXPERIMENTS. The President said he did not think impact had the slightest effect on a piece in breaking, and he did not think that impact on a notched piece would tell anything which could not be better told by steady loading. He then referred to experiments made in 1867 by Col. Maitland to ascertain the effect of sudden loading or shock. A strong tube was prepared by being accurately bored and furnished in the middle with a radial vent and a radial pressure gauge. Plugs of steel fitting the bore of the tube were screwed on to cach end of the specimen. These plugs were fixed in the tube, the annular space around the specimen being filled in some cases with quick-burning powder, and in others with gun-cotton air-spaced. On the charges being exploded through the vent the plugs were driven violently out of the tube in opposite directions, each carrying one half of the specimen. The elongations under these tests varied from 47 per cent. of 62 per cent. The fracture in all cases was silky and fibrous. With the largest charges of gun-cotton tried, giving presumably the most sudden strain, the specimen in several instances broke in two places, the central piece being cigar-shaped. This unexpected result of increased suddenness of strain giving increased elongation was probably due to the metal not having time to settle, as it were, in what spot to break. Under gradual tension the specimen was stretched very locally, and broke at the spot least able to sustain the strain. Under sudden tension the specimen stretched all over the operative part. The President then referred to diagrams on the walls in illustration of his arguments. In particular, he drew attention to the significance of local extension. Although its importance was not insisted upon in the papers, it was the particular point which marked the difference between materials that would or would not stand nicking. Whether the stress were by impact or by a steady transverse stress was not of the slightest importance. The material would stand the amount of work which it had in it, if every section of the material were stretched up to the point when the particles would no longer cohere. STANDARDISATION OF TESTS. Mr. Seaton, in reply, said that with regard to the President's remarks on notches, he explained that they were introduced to subject the material to similar stresses, were found in everyday use, and what had been said in the paper fully justified their use. He explained that parts were broken by small shocks applied thousands of times, and the shock that broke the piece was nothing like as great as the one that would be required to break the same piece when new with a few strokes. He was in accord with Mr. Longridge and in favour of a circular section. In answer to Professor Harbord about the irregularity of results, they had found very little variation with the same material, although in the case of bright steel rolled shafting there certainly was not the same regularity. There could be no doubt whatever as to the question of standardisation if the tests were to become recognised. One speaker had suggested that if the bar broke with twenty-four blows, it was four times as strong as one broken in six blows, and had asked if this was correct. That was not so; the bar which broke with twenty-four shocks was certainly stronger, but not in the proportion of 4 to 1. As to the method of breaking the bar, they aimed at doing so simply by shock, without introducing bending at all. In conclusion, he wished to thank everyone for the interest they had taken in the paper, and again explained that he did not in any way suggest that their method was the correct one, or the one that was to be followed. They had prepared the paper simply as a means of bringing this subject prominently before the Institution in order that some good might result from the discussion. |