26 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[January, 



ground in f roil I of Torr-house. This pusition is cnmmanding and centri- 

 oally situate, not only for Plymoutli, but for Devonpor/ anJ S/onehonse. 

 The reservoir could be made at moderate expense to hold six days' supply 

 for the entire population of the three towns, with an increase of 50 per 

 cent, or say 159,000 people, supposing that the large quantity of 30 gal- 

 lons per head per diem be required ; it would be 2T5 feet above high- 

 water, a heigiit sndicient lo give full fire engine Dower, at the most elevated 

 point in Plymouth or the neighbourhood, including the high quarter round 

 Lipson-terrace, which is now quite ^bove all water supply. 



Tije available supply is proposed to be taken fr<jm a water-shed district, 

 under tlie control of the Corporalion of I'lymouth, and contains about 

 5.000 acres. The minimum rain-fall. taken at 42 inches per annum on 

 5,000 acres, is 702,300,000 cubic feel per annum, representing an 

 average of 1.450 cubic feel per ininule. flowing oil the ground To make 

 this available for supplying l'lyni>'Ulb, we may assume that one-third 

 would unavoidably run to waste, which would leave a stream of 900 

 cubic feet per minute. If so much as 200 feet was let down for the mills 

 on the I'lym, — below the Head Weir, there would be 700 cubic feet per 

 minute, left for Plymouth. 



Now the quantity of 30 gallons per head for 150,000 people will require 

 only GOO cubic feet per minute, consequently there would still be an ample 

 margin ; but this is only to be secured as a regular supply, by forming 

 a Slore Reservoir on the River Phjtn, — by walHng or embanking up the 

 narrow and picturesque gorge below Sheepstor-hridge ; this done, 40 to 50 

 acres of waier may be gathered with a depth of 20 to 25 feet ; the land 

 is inexpensive, and the dam would be of a trifling cost. 



The foregoing outline of my plan has been described in a somewhat 

 retrograde form, so as to show the suggested improvements in the order 

 that they might be executed, and of their necessity. If fully carried out, 

 the purest water, in sufficient quantity, lo supply 150,000 people «'ith 30 

 gallons per head per diem, can be delivered into a settling and distributing 

 reservoir 275 feet above high-water, affording 00 feet of head to the highest 

 parts that can be built upon, and distant only two miles from the centres 

 of the towns of Plymouth, Devonport, and Slonehouse, 



The total expense, of course, cannot be precisely stated from the general 

 plans only that have formed my study, nor is it my object lo give precise 

 estimates, because if thought worthy of notice, there is sufficient to show 

 the line of policy that should direct to the results iu view. On a general 

 calculation the cost would be as follows : — 



For extending Services, Pipes, and Fire-plugs, &c. Hose- £ s. d. 



reels, and Stand-pipes in Piymoutb, say 4,(100 



For abandoning mills, purchasing leases. &c 



For Great Distributing Reservoir at Torr I itinnrt o n 



Fur Line of JIain from Torr to Plymoutti ! '°'''" " " 



For Tanks and Pipes across Manadon Valley ^ 



Improving Leat Course 1,000 



£20,000 II 

 For Store Reservoir on the River Plym, at Sheepstor-bridge 8.000 



Total £28,0011 



The report next proceeds to make some observations on the ad- 

 vantages tliat will arise from a surplus of water to the washing of 

 sewers, and how sewers might he formed in Plymouth ; and it con- 

 cludes hy showing the economy that might arise by amalgamating 

 the Plymouth works with those of Devonport and Stonehouse. 



VULCANISED INDIA-RUBBER JOINTS FOR WATER 

 AND GAS PIPES. 



From the Report of Thomas Wicksteeu, Esq., Engineer to ike East 

 London Waterworks, ^-c. 



On the 29th of February last, Mr. liroikedon* called my attention to a 

 new method of making the joints of socket-pipes for water and gas. He 

 exhibited a spigot and socket-pipe made of glass of 2 inches bore, and upon 

 the spigot stretched a ring of vulcanised india-rubber, the external diameter 

 of the ring, when stretched, being greater than the internal diameter of the 

 socket into whicli it was to he introduced. In stretciiing the ring upon the 

 extreme end of the spigot, care was taken to avoid twisting it. He then, 

 with very great e.ise, iinshe.d the spigot, with the ring upon it, into the 

 socket, and the operation of making the joint was completed. When tlie 

 spigot, was puslicd into the socket, the ring rolled along the pipe until the 

 end of the spigot came home, tlie ring remaining fixed about tlie middle of 

 the depth of tl)e socket. If the ring bad been twisted it would nut have 

 rolled in regularly, and would Dot therefore have been equally compressed. 



The facility with which the juint was made was very remarkable, the 

 wbole operation being completed in a minute, and in this respect the saving 

 of time and lalmur, as compared with that required for lead or wood joints, 

 is very considerable. > 



Mr. Urockedpn wished me to try experiments upon this new joint, and 

 make such investigations as I might consider necessary to satisfy myself of 

 its -value with a^view lo its general introduction. This I have done, and the 

 rwurt i& v^y flsvotj'ia)jla, \ 



+ 



* Of Ihe firm of Ulessrs. Mackintosh and Co. 



The facts to be ascertained were, the durability of the material as 

 compared with materials usually employed, its cnpability of resisting pres- 

 sure, and the cost of making the joint, all equally important in a commer- 

 cial point of view. 



First. As regards its dnrability. I consider it a question that should be 

 determined by chemists ; and the report of Mr. Arthur Aikin, given at the 

 end of this report, satisfied me of its superiority, in this respect, to lead or 

 wood ; and I believe practical experience, since the introduction of vul- 

 canised iurlia-rubher, fully corroborates these opinions. As, however, the 

 question of durability cannot be practically determined in a few years, and 

 as it is most important, in a commercial point of view, that the material 

 used for joints should be very <lurable ; so, the time since the introduction 

 of this material being comparatively shurt, I felt it was necessary to have 

 the opinions of those wlio were well qualified to give them upon the proba- 

 ble durability of the material, as compared with others now employed. 

 One fact is well worthy of notice, as regards the action of the products of 

 coal upon this material, especially as they appear to be the only liquids that 

 affect it. Naphtha, it appears, will dissolve simple or unvulcanised caout- 

 chouc, but only stvells it when vulcanised ; and thus the eifei:t, which for 

 some purposes would be injurious, for this purpose is advantageous, as the 

 effect of it is to make the joint tighter. 



As a general principle, there can be no doubt that, ceeteris paribus, the 

 more elastic the material for a joint the better, as the friction of an elastic 

 body pressing against the pipes is much greater than that of an inelastic 

 body; and hence the resistance to pressure, or force exerted to displace it, 

 must be much greater. In a joint made with lead, the resistance to the 

 pressure is owing to the melted lead filling up any irregularities in the 

 surfaces of the spigot and socket, thus forming a key, and also to the com- 

 pression of the lead, effected in *' setting up." Now, this etfect does not 

 extend above a quarter of an inch beyond the external face of the joint, 

 and, therefore, it is most important that this operation should be carefully 

 performed. Great force is employed in " setting up ;" it is, therefore, neces- 

 sary to have the thickness of the sockets greater than the rest of the pipe, 

 to prevent its splitting during this operation. Again, in a wood joint, the 

 operation of driving in the wooden wedge causes it to be compressed; thus 

 the wedge which, before driving, is from ^ an inch to £tbs of an inch in 

 thickness, is compressed to the thickness of gths of an inch when in its 

 place, this compressed part being about 1 inch in depth of the socket. Now, 

 in this operation, although the wedge may he driven in so tight that neither 

 air nor water can pass through, and so far this cause of decay avoided, 

 nevertheless, the fibres of the wood are injured by the operation of driving, 

 and its elasticity consequently much impaired. In this case also it is neces- 

 sary to have the sockets made strong to resist the force applied in driving in 

 the wedges. With a body as elastic as the vulcanised india-rubber, how- 

 ever, such force is not necessary, the material cannot he forced or driven in 

 with a hammer, it is merely rolled in ; and the ring which, before compres- 

 sion, is round, when its place takes the form of a flat belt instead of a cir- 

 cular ring. Thus, supposing the thickness of a ring to be fths of an inch 

 diameter before compression, when rolled into the socket, with a space of 

 i of an inch between the spigot and socket, it becomes a belt of ^"^ x ^4 ; 

 or the depth of the belt is more than double its thickness; and this elastic 

 flat belt of rubber, which has naturally an excessive tendency to resist 

 sliding, is constantly endeavouring to resume its circular form, and hence 

 the great friction exerted on the sides of the pipes, while in this compressed 

 state. 



[Here follows an account of seventeen different experiments made by Mr. 

 Wicksteed to test the efficiency of these joints.] 



The time occupied in these trials has been above five months, and I am 

 now enabled to speak very confidently of the value of the new joints. 



It appears that, for a 4-inch joint, the space between the spigot and socket 

 being -} of an inch all round, the vulcanised india-rubber ring should 

 weigh 14 ounce, and for a 12-inch ring; the space between the spigot and 

 socket being the same, viz., J of an inch, the weight of the ring should be 

 5} ounces. 



Section of spigot-end of pipe. 



A, end fillet or belt. B, upper fillet. C, section of vulcanised india.rubber ring. 



The spigot and socket ends of pipes to suit the vulcanised india-rubber 

 rings should he formed as follows : — The depth of the socket for all pipes 

 up to 12 inches, which is the largest I have experimented upon, should be 

 3.i inches; the thickness of the joint or space between the outside of the 

 spigot and inside the socket, should be J of an inch. There will be no oc- 



