28 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[January, 



would swell, and tlais render still more effectual a fastening which was snfR- 

 tienlly so hefore. 'I'he strongest liquid amniouia. as 1 know by experiment, 

 has no sokent action whatever, even on common caoutouche, hy digesting in 

 it for several months. Sulphuretted hydrogen has no sensiide cft'ect on 

 common caoutchouc immersed in it for some days. If by loUL'-continued 

 action on vulcanized caoutchouc, any sulphur was taken np, no injury to the 

 ring would result from this; for vulcanized caoutchouc may contain a great 

 excess of sulphur, without at all impairing its elasticity and other valuable 

 properties. 



With regard to the durability of vulcainzed caoutchouc compared with 

 that of wood or lead, which, 1 believe, are the only substances at present 

 used in joining iron pipes, the following circumstances must be taken into 

 consideration. 



The compression and violence which wood nndergoes in the act of being 

 driven in, will more or less damage its texture, and weaken the lateral co- 

 hesion of its fibres. Caoutchouc being without visible pores, and being of a 

 perfectiv uniform consistence, and possessed of great elastiiitv, will not only 

 exclude'air and moisture from the space which it occupies, Imt is scarcely 

 susceptible of mechanical itjury, even from the strongest compression. 



Lead is no mote porous than caoutchouc, but being almost totally inelastic, 

 will, on this account, be a less effeclual preventive of leakage. Some 

 galvanic action will probably take place between the lead and iron tending 

 to oxidise this latter ; and, when galvanic action has ceased, from the inter- 

 position of a layer of oxide of irorj between the two metallic surfaces, the 

 lead itself will become oxidised superficially, from the combined eft'ect of 

 air and moisture. 



I do not, therefore, see any reason to doubt that rings of vulcanised 

 caoutchouc, « ben used as a fastening of iron pipes employed in the con- 

 veyance of water or coal gas, would be, at least, as durable as the best of 

 the methods now practised, and probably more secure from leakage. 



FROCBEDINGS OF SCIBNTIFIC SOCIBTIES. 



SOCIETY OF ARTS, LONDON. 



Nov. 29, 1843. — J. K. Brunel, Esq., in the Chair. 



" On HydravMc Pressure Engines, and on the employment of High Falls of 

 Water, actiny by their Weight or Pressure upon a Piston workiuy in a 

 Cylinder, to produce a Reciprocating or Allernatiny Motion." By Joseph 

 Glynn, Esq., F.R.S. 



"It appears," observed Mr. Glynn, "that in the year 1769, this subject 

 had been brought before the Society of Arts hy Mr. Smeaton, the celebrated 

 engineer, whose construction of the Eddystoue lighthouse has since served 

 as a guide in similar works. 



Owing to the great improvement subsequently made in the steam-engine, 

 hy Watt, water-engines of all kinds were thrown into abeyance, and the 

 water-pressure engine remained unemployed in England until its use was 

 revived by Trevithick, who was distinguished liy the invention of loco.notive 

 engines to be used on railways, or rather upon the tramways of his time. 

 Trevithick erected several water-pressure engines, and in 1801 he made one 

 for a lead mine in Derbyshire, which is still working well in the Alport 

 Mines near Bakewell. In 1811, the proprietors of the mines, by the advice 

 of Mr. John Taylor, resolved to erect a very powerful engine of this kind, 

 to clear the mines from water; this was made by the Butterley company, 

 under the direction of Mr. Glynn, and set to woik early in the following 

 vear. It is one of the most powerful and efficient engines of this kind 

 idtherto made ; the work it performs is equal to lli8-hclr^e powei.andits 

 useful effect is equal to 70 per cent, of the theoretic power of the water 

 fall. The column of water in this instance is 132 feet high, the stroke of 

 the piston is 10 feet, and the diameter of the cylinder 50 inches; conse- 

 quently, the pleasure on the piston is equal to a weight of 50 tons. This 

 engine is capable of making 7 strokes per minute, without any concussion in 

 the descending column. An excellent model of this engine, now in the Mu- 

 seura of Economic Geology, was made by Mr. Jordan, whose admirable in- 

 vention of machinery for carving in wood has since established his reputa- 

 tion for mechanical skill. — The water-pressure engine, nUtiough neglected 

 in England, has been extensively used in Germany, and drawings of some of 

 the best German engines were exhibited, to illustrate the paper. 



A lengthened discussion followed the reading of the paper, in which Mr. 

 JoKDAN suggested a means of overcoming the concussion, hitherto so ob- 

 jeciiunable in the working of all engines of this class.— Mr. Glynn also 

 stated the situations in which he considered hydraulic engines could be 

 advantageously employed, and in which it would be impossible to make use 

 of any class of water wheel. He also described an ingenious a|)plication of 

 hydraulic power, in the case of a crane used on the Quay at Liverpool. 



The thanks of the meeting were presented to Mr. Glynn for his commu- 

 nication. 



Messrs. Staite and Petrie were present at this meeting, and exhibited 

 their Electric Light, and showed the prismatic ray, and the ray concentrated 

 by means of a lens. — A lengthened discussion ensued, as to the peculiar 

 form of the shadow from the Hame of a candle, and the band of li^lit which 

 surrounded it. 



The thanks of the meetiui; were presented to Messrs. Staite and Petrie, 

 who promised on an early eveniiig to submit a paper on the two leading fea- 

 tures of the invention — namely, rendering the light permanent by means of 

 a self-regulating magnetic apparatus, also rendering the system economical 

 by allowing only so niucli of ilie current to pass through the electroes as is 

 developed in light; and also to make a statement as to the cost of producing 

 and maintaining the light. 



Mr. C. RcDiNG submitted a paper on Mr. J. B. Piatti's " Compressed-Air 

 Atmospheric Railway," and a model of the tube, valve, and piston were 

 exhibited. 



Dec. 6, 1848.— J. L. Ricakdo. Esq., M.P., in the Chair. 



Mr. T. B. Jordan read a paper " On improvements in Carving machinery." 

 The three great improvements which Mr. Jordan has effected in his carving 

 machine are as follows: — Firstly, in the construction of what he terms a 

 Vertical Machine. The peculiarity of this arrangement is that it enables 

 liim to carve blocks of stone of any required size, for architectural or deco- 

 rative purposes, without having to move the weight of the block, as would 

 be the case if it was placed on the horizontal bed of his first machine. The 

 cutting drills are, by the vertical machine, brought in contact at right angles 

 to the face of the stone, the stone itself being placed on a chuck or centre, 

 upon which it is made to revolve, so as to afford the necessary facility for 

 bringing every portion of the surface into contact with the drill. — Secondly, 

 in applying mathematical instruments on the floating tables to the produc- 

 tion of working mouldings from drawings, without the use of models. This 

 he does by having the cutting edges of the drills made in the form of one- 

 half of the section of the moulding to be produced. — Thirdly, in aft'ording 

 the means of producing a reverse copy of any required pattern, so that the 

 two curves on a chair-back, or other piece of furniture, can be cut out from 

 a single mould at one and the same time. This he effects hy dividing the 

 upper floating table info two parts, and fixing a centre under the machine 

 and between the two floating tables ; on this centre is a fixed lever, which is 

 connected at each end, by means of iron rods, to the floating tables, so that 

 whatever motion is given to the right-hand table, is exactly copied, in a 

 reverse direction, by the left-hand table. This is the case only so long as 

 the radii of the two arms of the fixed lever are exactly alike; but by altering 

 the length of either arm, a fourth improvement is efl'ected, as the inventor 

 is enabled to compress a pattern so as to produce a narrow panel from an 

 original of much greater breadth. 



A model of the Horizontal machine, and diagrams of the Vertical machine, 

 with specimens of work cut by each, were exhibited. 



Dec. 13, 1848.— T. Webster, Esq., F.R.S. , in the Chair. 



" On the Present State of Electricity, as applied to Telegraphs." By 

 Mr. N. J. Holmes. 



Mr. Holmes, in bringing the subject forward, stated that it was his inten- 

 tion on this occasion to consider only the principles of the best known forms 

 of existing telegraphs, and not to enter into the various modifications into 

 which the subject had extended, as many of the recent adaptations were 

 merely simple evasions of original patents, without any claim to merit for 

 the advancement of science. Having given a succinct, but comprehensive, 

 historv of the state of electricity, with respect to the application, sicbjudice, 

 from i746 to 1800, when Volta'discovered that the current obtained from 

 his pile had the property of overcoming the difficulties presented by the use 

 of free electricitv, be dated the progressive advancement of the science from 

 (Ersted's grand discovery, in 1S19, of the rotatory influence exercised by an 

 electric current upon a magnetic needle, immediately followed hy that of 

 Arago, in the formation of'^the electro magnet. The intiuductjon of the 

 telegraph into this country did not take place until the year 1837, at which 

 period the subject was occupying the attention of the scientific, and many 

 were endeavouring to carry out practically the idea, hut without success ; 

 and it was not nntil Professor Wheatstone's researches into the more theo- 

 retical portion of the science, that the requisite perfection was obtained. 

 The existing telegraphs were classified into two great divisions— namely, 

 those of a mechanical nature, in which the inter venlion of clockwork, set in 

 motion through the agency of electricity, was used to produce the necessary 

 indication; and others embracing a more theoretical construction, depending 

 upon the diiect action of the ( urrent, either hy induction upon a magnetic 

 bar, producing deflection, or by the decomposition of certain chemical solu- 

 tions, placed so as to form a part of the metallic circuit. With respect to 

 telegraphs generally, it was stated that their adoption could not be advo- 

 cated for either railway or commercial purposes, where great attention 

 could not be bestowed on their working in detail — the imperfections arising 

 from their mechanical liabilities destroying their utility. The only railway in 

 this country, out of the 2,000 miles of telegraph laid down, upon which they 

 had been adopted, was the South Devon, and there they were used to give 

 the signals for starting the fixed engines in connection with the atmospheric 

 svsteni. Previously to the abandonment of that principle, such was the 

 perfpition to which Mr. Holmes (under whose superintendence they were 

 erected) had arrived, that as many as 2,000 signals were sometimes given 

 through the series without the commission of a single error. 



After adverting to the numerous varieties of printing telegraphs and 

 alarums, Mr. Holmes exhibited his new signal, as a substitute for the old 

 clockwork bell, producing the sound by means of an air-whistle. Mr. 

 Holmes then proceeded to the second division, pointing out the various 



