1846.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



Sd 



best manner. The paper gave rise to a long and interesting discussion, whii-.h 

 elicited tlie opinions of engineers and scientific men present on the merits , 

 Mr. Bcdmer's plan. Tlie principle on which his engines are constructed 

 were approved by all who spoke on the subject, and the thanks of the 

 meeting were unanimously accorded to the author. The next paper read was 

 a sequel to the former by the same author, on improved crank axles and axle 

 boxes, by which greater security and economy are obtained in railway trains 

 running at liigli velocities. There were other papers on the list of the 

 evening, one of them containing a valuable discovery by Mr. Nott, on the 

 nature of the Photographic rays, and a method by which a great improvement 

 is effected in Daguerreotype pictures. But the lenstb and interest of the 

 discussion rendered it necessary to postpone that and the other communi- 

 cations to a future meeting. The meeting was crowded and deeply interesting, 

 and augurs well for the prosperity of the society under the new regime. 



ROYAL SCOTTISH SOCIETY OF ARTS. 

 Monday, Nov. 21, 1845 — John Beatson Bell, Esq., in the Chair. 



The following communications were made : — 



" Description niiil Dr<iwing of a new Rijie Breech." By Mr. Thojjas 

 MoDLD, gnnmalicr, Slirling. Communicated by Mr. Burns ofGarvald. 

 Sir. Mould's method is to attach two spiral "ribs" to the breecli only, f»r 

 about two inches where it screws into the barrel, and not to the barrel it- 

 self, as in the comnion mctliod ; the ribs being made to describe a curve 

 equal to a whole turu in twelve inches. The breech, after being linished, 

 is case-hardened. The barrel can be made much longer oa iNlr. Mould's 

 plan without danger of stripping the ball. After tiring with this riHe, the 

 tract of the ball can be clearly seen runninj in a spiral direction aloiin the 

 inside of the barrel, if the breech be unscrewed, and the barrel be held like 

 a telescope. The piece is also said to be much easier loaded. Referred 

 to a Committee. 



" Description and Drawing of a Railway Alaruin", by which the guard 

 may communicate with the Kngineer. By Mr. Andrew Cariuck. This 

 proposal is for a communication to be elfected from the locomotive all 

 along the train by means of rods passing beneath each carriage, which are 

 united by chains after the carriages are attached to each other. On the 

 guard pulling the lever attaclied to this, a bell is struck on the locomotive 

 so as to give warning to the engineer when any thing is wrong, or when it 

 is wished to stop the train. 



" Description and Drawing of a Railway Indicator," for showing at night, 

 or in dense fogs, the speed of the engine, or distance it has travelled from 

 the station. ]5y the Same. This iodicator consists of a screw working 

 into a piuion on the axle of the driving wheel, whicli carries a spindle that 

 ■works by means of a train of wheels, upon one that carries a hand or 

 pointer, showing how many miles the eugiue has travelled from the station. 

 Mr. Carrick recommends that, at each station, the engineer sets the pointer 

 to zero, aud thus he will know almost exactly where the train is, even in 

 the darkest night or in dense fogs. 



" Description anrf Drawing of another Railway Indicator." By tlie Same. 

 This is another form of the indicator. It consists in having studs hxed 

 along the railway at each mile, which oq the engine passing over them, 

 come in contact with a bell crauk, and ring a bell lised on the locomotive. 

 The engineer can thus count the number of miles passed over. 



Monday, December 8. — John Beatson Bell, Esq., V.P., in the Chair. 



The following communications were made : — 



Notice relative to tlie properties of 



Patent Intonaco Cement, with illustrative specimens. By Mrs. Map.- 

 GARET Henrietta AIahshall, Millport. 



It was Slated that the principal claims to notice possessed by this ce- 

 ment, are its cheapness, hardness, and durability, and the almost boundless 

 variety of purposes to v\hich it may be usually applied. Tliat in architec- 

 ture, it is alike litied for walls, flooring, ceiling, and pointing slates, which 

 it unites into one solid immoveable body. That it sets in a few hours, aud 

 dries so rapidly, that a house plastered with it may with perfect safety be 

 inhabited in eight days. That it is alike hard through its whole substance ; 

 and, even as exterior cement, in imitation of stone, has remained uninjured 

 and uurdtered in all weatliers, never having been known to peel or throw 

 oil' any salt from the surface. That it is such a slow conductor of heat, 

 tliat iron of equal thickness, exposed to equal degrees, showed a balance 

 of 6,! in favour of the Intonaco, cousequeatly it offers a very great security 

 from fire. That as it shows at least as great a power of resisting damp, 

 lathing may be entirely dispensed with, wherever it is used as wall plaster; 

 and partitions formed of it, according to the plan of the patentee, only two 

 inches in thickness, present a much firmer body, and more eti'eclual deaf- 

 ening, than the i\ inch double lath partitions at present in use ; besides 

 being cheaper ; — and that no vermin of any description can penetrate or 

 lodge iu walls or partitions done with it. That this cement oilers a per- 

 fectly new art of imitating marble, which, imnioveably united to the sur- 

 face of sandstone, and higlily polished, will bear exposure to any weallier. 

 Every style of ancient ornanieutal (looting can be imitated to perfection at 

 moderate cost. 1'hat it forms an entirely new ground either for mural, or 

 easel oil painting : the finished paintings possessing all the advantages of 

 fresco, united to greater depth and brilliancy, and incalculably greater ease 

 of execution. That as a ground for gilding, it has received the highest 



aporobation of practical men; and is ready for the gold in 24 hours after 

 moulding or mode\ 



Account of Experiments on Electro-Culture. — By Andrew Fvfc, 

 M.D., F.K.S E., Professor of Medicine and of Chemistry, University and 

 King's College, Aberdeen. 



In this paper the results of trials on the application of electricity t.> 

 vegetation, as recommended by Dr. Foster, were first stated, the wire* 

 being applied to cabbages, &c. In these experiments Dr. Fyfe did not 

 find the slightest benefit to accrue. At the time that the trials were in 

 progress, experiments were also instituted with the view of ascertaining 

 whether there was an electric current along the wire, which was done by 

 the use of the gold leaf electrometer, and by delicate galvanometers. In 

 all of these, there was not the slightest indication of electric current. 



Dr. Fyfe's paper afterwards gave the results of trials on the applicatioQ 

 of galvanic electricity, this agent being applied in a varietv of ways, to 

 peas, beans, onions, potatoes. In some of these the galvanism was applied 

 by sinking metallic plates in the ground, and connecting them with wires, 

 sometimes sunk in the earth, at other times left above it, and in contacti 

 with the plants. In other trials the galvanism was applied by the use of 

 batteries, with wliich galvanometers were connected ; the trials, in some 

 cases, being continued forseveral weeks. In all, not the slightest dillerenco 

 could be observed between the products of the galvanised and non-galva- 

 nised vegetable. Iu the case of the potatoes the products were, in one 

 trial, as 37^ for the galvanised to 3;i for the non-galvanised. In another, 

 it was as 4(i^ for the galvanised to 5U for the non-galvanised. Taking th-; 

 average of aM the trials, the results were as lOU for the galvanised to 10f« 

 for the non-galvanised. 



From the results of his numerous trials, Dr. Fyfe concluded that no 

 benefit whatever was observed to follow the application of electricity, either 

 by the mode recommended by Dr. Foster, or by galvanic ■di'Ctricity — at 

 the same time, he stated, that though in these trials no benefit resulted, he 

 VNas far from asserting that electricity would not be found beneficial ; th© 

 subject was worthy of prosecution, and he hiiped that others would be in- 

 duced to prosecute it, and to give it the scrutiny to wiiich it was entitled. 



AT.MOSPIIERIC TRACTION. 



The power employed in exhausting the Main Pipe compared with the power- 

 exerted 6y the Train Piston ; Friction a«rf Leaka HE heiny disreyards't 



m both cases. » 



I presume that Mr. Ilaydon's formula;* are general ones, i. e. independenj 

 of the dimensions of the tiilies and pumps, as likewise of the length of the 

 stroke of the jiunip and the number of the strokes ; and that consequently i 

 may assume, ./"or the purpose of explanation, any dimensions, &c., which I 

 find most easy to deal with, however extravagant such dimensions ma/ 

 otherwise appear. 



The preliminary exhaustion 1 will suppose to be effected by means of a 

 piston placed witiiin the main pipe itself. To produce the degree of ex- 

 liaustion assumed by Mr. llaydon, viz: one third of the atmospheric pressure, 

 or 511), per square inch, such piston must obviously be moved along two- 

 thirds of the length of the main; its motion terminating at the end opposita 

 to that from whieli the train piston is to start. 



The power, necessary so to move this piston, may he estimated as follows, 

 (taking each side separately and considering only the effect upon one square 

 inch). 



Call the length of the main a, call f of its length b, and ^ of its length c,, 

 then a = b + c. 



Opposed to the motion of this piston, through b, there would be the 

 constant atmospheric pressure of lolb = 15 b. 



Assisting its motion throughout i, there would be a pressure varying froiG 

 lalli at the commencement, to 61b. at the termination : if we call the avej-ayo- 

 of this varying pressure ,r, then the assisting force would be x b, and the 

 general expression of the resistance is 15 b — x b, or (15 — x) b, to be over- 

 come in effecting the preliminary exhaustion down to 51b pressure per square 

 Inch. 



Thetrain piston being now ready to start, the next object is to maintain, 

 iii front of it, while it travels, the degree of exhaustion just specified, viz. : 

 51b per inch ; and for this purpose, I will suppose a second piston to bft 

 placed also within the main pipe, at a point some little in advance of tin 

 train piston, and that the power by which it (the second piston) is to b( 

 moved along the main, is so regulated as to draw it along exactly at th« 

 same rate as that at which the train piston itself travel?, whereby the space 

 between the two, may not become larger or smaller, as that, if it occurred 

 would change the degree of exhaustion in front of the train piston. 



The power necessary to move this e.i'/ia(«''0« '«a"'''2!'""y piston may hi 

 estimated as follows : 



It must move through a, (the length of the main): opposed to its motioi> 

 there would be a pressure at the outset of 51b, but by the time the»pistonr 

 had moved through ; of the length of the main (or b) the pressure woul* 

 have increased to 151b. This varying pressure being precisely equal ii> 

 continuance and intensity to the assisting pressure of the preliminary ex- 

 haustion, its averaye may like that be called ,r, and its total .r b. 



* Pan 98, page 335. 



