1849.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



27 



casion for extra strenglit in the sockets, as they are not exposed to any 

 blows or to the force of the wedge in making the joint, as in lead and wood 

 joints. The spiijot should have a square head or belt -nfths of an inch 

 thick, and ' an inch deep, cast on the end, then a clear space of 2i inches, 

 and then another helt of the same dimensions, as shown in the engraving. 



This will allow a i)lay of tu*'' "' "" '■"''' ''" ■'"'"id, and the upper belt 

 will effectually prevent the joint hluwing out ; shouM there be any slight 

 deficieucy of thickness in the india-rubber ring, or should the ring be put 

 on the spigot carelessly, so as not to roll regularly ; this, however, can 

 scarcely ever happen, as the fillet at the end of the spigot will be a guide to 

 the workman, and very much facilitate the fixing of tbe ring properly. 



I have calculated the weight and cost of 100 rings of various sizes, which 

 will be the number required for 300 yards of pipes, as follows : — 



lead or wood joints, 1 have in the following statement included the mate- 

 rial, tbe labour in making the joint, and the excavation, and filling in of the 

 trench only, hut including 10 per cent, profit : — 



At per yard run. 



Vulcanised India-rubber. 



Lead. 

 9. d. 



Wood, 

 s. d. 



India- 

 rubber, 

 s. d. 



•'■m 



cheaper than 

 Lsad. 



cheaper than 

 Wood. 



4 inch 6fu 4-^ 3.^ 100 per cent.f 42 per cent. 



12 inch 1 7 11 9^;, 91 „ 11 „ 



3,4,5,0, 7, S, "I 



9,10,ll,12,in. I 10 6 2 5 2 93 „ 19 „ 



one yard of each J 



Taking one yard of each sized pipe, from three inches to 12 inches inclu- 

 sive, and in addition to the above, adding the average cost of carting the 

 pipes to the trench, removing surplus earth, repairing drains, lead pipes, &c., 

 and all other charges and risks, and guarantee for twelve months, excepting 

 the charges of the Commissioners of Uoads or Streets for paving, &c., the 

 cost will be as follows : — 



India rubber India-rubber 



Lead. Wood. India-rubber. cheaper than lead. cheaper than wooJ. 



23s. lOrf. 20s. 6(/. 19s. 6rf. 22 percent. 5 per cent. 



The prices given may vary according to the locality and nature of the 

 ground, but, I believe, will he found in every case very moderate for good 

 and sound work. Where there is rock, or paved or Macadamised roads to 

 be excavated fur tbe trencb, the saving in laying the joints with India- 

 rubber rings will be very great, as the extra excavation required round the 

 Joint (or lead, cement, or wood joints, to afford sufBcient room for the joint- 

 maker to work all round the joint, will not be required for the India-rubber 

 joints ; and hence the saving in excavating through rock, and excavating or 

 taking up and renewing the paved and Macadamised roads, will be con- 

 siderable. 



When the wood joints are used (and they have been used very extensively 

 in the East London district for the last sixteen or seventeen years, and found 

 to answer remarkably well), it is necessary to expose the joints to the pres- 

 sure of water they are intended to bear, before the ground is filled in, to be 

 certain that the joints are tight ; hence, uidess in counection with mains 

 already charged, tbey cannot be employed, for the expense of working a 

 force pump to fill every length of pipe before it is covered, swallows up all 

 the saving that, under other and more favourable circumstances, is effected ; 

 so that for new towns, or places where there are no charged mains already 

 in existence, they cannot be used; and for gas pipes they are not at all ap- 

 plicable. 



An objection was made many years ago to tbe wooden joints ; that where 

 the pipes had to be much curved, it would not be safe to make an unequal 

 joint thick on one side and thin on the other, while with lead this might be 

 safely done by a clever joint-maker. The same objection may be made to 

 the proposed joint, on account of the belts preventing a greater play than 

 ■Jj-th of an inch in the socket, — tbe answer given in the first instance will 

 do in the second, should it be made; viz., that the number of joints required 

 to be so made, formed an inconsideral)le percentage upon the whole number 

 made, and, therefore, formed no sufficient objection to ihe general use of a 

 cheaper joint. 



As regards its applicability to gas pipes, I have some hesitation in giving 

 a strong opinion ; but as Mr. Aikin's Report proves that it is a durable mate- 

 rial, and is not injuriously affected by the producis of coal gas which collect 



* The wholesale price of vulcanised india-rubberj fur small quantities it is 6s, per lb. 



t 100 per cent, cheaper is an erroneous expression ; it would make the india-rubber cost 

 nothing, for if iOO per cent, be taken from 1' 0. there remains 0. It should be 60, 4d, and 

 is per cent, less than lead, and 29, 10, and It! percent, less tlmn wood. 



in the pipes ; and as it appears from my experiments that the joint can stand 

 an enormous pressure, I think it may, probably, be found tbe best material 

 that could be used for a gas joint, i believe it will be admitted, that with 

 the materials ordinarily emjiloyed in joining gas pipes, it is difficult to fill 

 the joint so thoroughly as to prevent tbe escape of gas, which the colour of 

 tbe earth near the joints of gas pipes will prove : and although a lead or 

 wood joint may be made capable of withstanding great pressure, and so as 

 to prevent water leaking through, nevertheless gan will escape through. 

 Reasoning upon the matter would, therefore, lead to the conclusion, that if 

 a very elastic body is used, pressing with great force on all the surfaces of 

 the iron in contact with it, so as to fill every space, there is much greater 

 certainty of forming a tight joint than with a non-elastie substance, where 

 the density of tbe material is all that prevents the escape of jras; it must 

 be borne in mind that the India-rubber is impervious, and can never be 

 liable to have fissures in it, or pores through it, which may be the case with 

 lead, cement, or wood, if not perfectly made, — not so large as to allow a 

 liquid to pass through, but sufficiently so as to allow gas to pass through. 



As regards pipes made of earthenware or glass, or other brittle material, 

 which would be broken, if it were attempted to make joints of lead or 

 wood, to witiistand a pressure of water, this material is very applicable, as 

 no force is applied in making tbe joint that would in the slightest degree 

 tend to split or break the socket of the pipe. This joint removes the only 

 mechanical objection that I believe exists to the use of these materials ; but 

 tbe chances of breaking when laid, and the cost of the pipes when so joined 

 (increased by the shortness of the lengths of the pipes requiring a greater 

 number of joints), are questions to be considered by those who propose 

 using such materials. It appears that none of tbe products of the sewers 

 would injuriously affect tbe vulcanized India-rubber. The improvement in 

 making the india-rubber rings since I received tbe first for trial is very great. 

 The first set varied in thickness and weight very.; much ; tbe last are as re- 

 gular in thickness, as can be proved by the weights of several of the same 

 size being as nearly as possible the same. This is most important, as a va- 

 riation in weight, which is the same as a variation in thickness, would pre- 

 vent the cerlainty of tightness of the joint. 1 have, nevertheless, in the 

 weights given in the table, allowed an extra weight as a precaution. 



In conclusion, I beg leave to say, that it appears that for strength, dura- 

 bUity, resistance to pressure, and for tbe closeness of the joint preventing the 

 escape of gases, this material is better suited than the ordinary materials in 

 use; and, that the cost of the joint is less than tbe cost of those inordinary 

 use for iron pipes. 



REPORT OF ARTHUR AIKIN, ESQ., F.L.S., ETC, 



Will Rings of Vulcanized Caoutchouc, when used as Fastenings of Cast- 

 iron Pipes, retain their Elasticity, and what will be their probable Du- 

 rability ? 



The resilient spring of vulcanized caoutchouc is far more complete than 

 that of the caoutchouc not vulcanized. In other words, the former is far 

 liable to tire than tbe latter. Caoutchouc is vulcanized by combination with 

 a certain small proportion of sulphur. As long, therefore, as caoutchouc 

 remains vulcanized, that is, as long as it retains its sulphur, it may be ex- 

 pected to retain those qualities by which it is characterised. But iron has 

 a strong attraction for sulphur. Is it not, therefore, probable that ml- 

 canized caoutchouc remaining long in contact with iron, may give up its 

 sulphur to this latter, and thus be reduced to the state of common caout- 

 chouc .' 



I see no satisfactory way of bringing this question to the test of experi- 

 ment, as both cast-iron and common bar uot unfrequently contain sulphur in 

 various proportions. Tbe rings of vulcanized caoutchouc that I have seen 

 taken out of iron pipes return to their original form as soon as tlie nip or 

 strong compression to which they were subject while in the pipes has been 

 relieved ; and they are stained externally by a little oxide of iron rubbed off 

 from the inner surface of the pipe, in consequence of the strong friction and 

 compression to which they are exposed in the act of inserting one pipe into 

 the other, beyond this merely superficial attrition, I do not think that any 

 sensible action would take place between the ring and the iron, even for a 

 very long time, at common temperatures. 



If tbe pipes are intended tor the conveyance of water, the exposure of 

 the projecting edge of tbe ring to this liquid at common temperatures can- 

 not possibly have any injurious effect ; for I have boiled vulcanized as well 

 as common caoutchouc tor an hour in water at 300°, and the pieces, when 

 they have become dry, have shown no diminution of their respective degrees 

 of elasticity. If the pipes are to be employed in conveying coal gas, the 

 original question becomes complicated with the consideration, how far the 

 volatile products of the distillation of coal are capable of acting on vul- 

 canized caoutchouc? The principal matters driven off from coal during its 

 distillation are carburetted hydrogen and defiant gas, sulphuretted hydrogen, 

 ammonia, tar. I believe, that in a very short time the projecting edges of 

 the vulcanized rings would be covered with a thin layer of tar, which would 

 effectually prevent their contact with the other matters, even assuming these 

 latter to have any action on vulcanized caoutchouc. Naptha, the product of 

 the rectification of coal tar, is capable of dissolving caoutchouc; but the 

 only effect which it has, even when boiling hot, on vulcanized caoutchouc, is 

 to cause it to swell. If the crude tar should have any such effect (which I 

 doubt), the consequence would be, that the projecting edge of the ring 



5* 



