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THE CIVIL ENGINEER AND ARCHITECTS JOURNAL 



[December, 



PF.OC3SDI3IGS OP SCISHTZFIC SOCIETIES. 



INSTITUTION OF CIVIL ENGrSEERS. 

 June 8. — The President in the Chair. 



The following weic elected : John Ball and Adalbert Morawski (of the 

 Grand Ducliy of Poscn), as .\ssociates. 



" Description of Ste])heruion's Theatre Machinery." By J. B. Birch, 

 Grad. Inst. C. E. 



In this communication the author describes a system of machinery which 

 was erected for the purpose of avoiding the confusion, mistakes, and noise, 

 consequent upon the number of men usually employed in the stage depart- 

 ment of a thcitre, and with a reduced number of meu to effect more per- 

 fectly all the operations required there. 



The apparatus provides means for shifting simultaneously and without 

 noise, any numlicr of distinct pieces of scenery, bringing at the same time 

 into view other scenes to replace them. The general arrangement of the 

 machinery for effecting this is fully described. 



The iuterior of the house between the basement and the roof, is divided 

 into four compartments, viz. : 



1. A raised platform on which the gearing for working the stage traps is 

 placed. The trap frames are mounted upon rollers; they traverse on the 

 lower platform in every direction ; and when brought under the apertnres 

 in the stage, allow the traps to sink or rise steadily at any required speed. 

 ' 2. The stage, with its traps of various dimensions, including a consider- 

 able portion formed to rise or fall by suitable machinery, and called the 

 sinking stage. 



3. The lower flies or coiTidor, between wliich and the stage a-e placed 

 the wings or side scenes, and the Ijorder frames are suspended. 



4. Tlie upper flies upon wliich is placed the machinery to communicate 

 motion to the whole, from the upper horizontal shaft, by means of bevel 

 gear, provided with double clutches to reverse the motion and shafts, on the 

 lower ends of wliich are the slow-motion wlieels and drums, au endless chain 

 is driven horizontally in either direction ; to this are attached the borders 

 representing clouds, foliage, arches, &c. 



The side scenes or wing frames, the number of which is determined by 

 the depth of the stage, may be either flat, circular, or triangular, and receive 

 a rotary motion, combined with or apart from a forward r.nd backward 

 movement at pleasure, and can be placed at any desired angle to the au- 

 dience. At every change of the scene they revolve through 120' or \ of a 

 circle, and the scenes when removed from sight are replaced by those which 

 are to succeed them. The traversing frames revolve on a centre, and are 

 suspended from the border frames, or from the upper p.art of the theatre, for 

 crossing the stage in any direction, and at any given inclination. Several 

 improvements in the mode of lighting the stage and house have been intro- 

 duced with the machinerv- ; they are more fully referred to in the detailed 

 description which accompanies the ten elaborate drawings sent with this 

 communication. 



" On the Combustion of Anthracite, and its value as 'a Fuel for Steam 

 Engine and otiier Furnaces." By Andrew Fyfe, M.D. 



Anthracite, although known as a valuable fuel for particular purposes, is 

 so ditficnlt of combustion, that it has hitherto been very partially brought 

 into use; it has, however, become desirable to introduce it more jjeuerally, 

 and the author having been engaged in testing the value of Jlr. Bell's patent 

 fnmace, was induced to make some experiments on the use of anthracite in 

 conjunction with that system. 



The objects sought to be obtained by the apparatus are, to insure a larger 

 amount of evaporation, by passing heated air, unmixed with the products of 

 combustion, through tubes in the boiler and surrounded by tlie water, thus 

 increasing the cva])orating surface ; and that the surplus caloric taken origi- 

 nally from the fuel, and not given out iu its passage through the water, 

 should be beneficially used in aiding the combustion beneath the boiler. 



It has l)ec>n found in the manufacture of iron that anthracite could be ad- 

 vantageously used by means of heated air ; the author therefore considered 

 that the experiments upon this apparatus (the intrinsic merits of which he 

 does not at all discuss in this communication), afforded an advantageous 

 opportunity for ascertaining in what manner this fuel could be successfully 

 employed under steam boilers. 



The anthracite supplied to tlie autliorwas unfortunately of inferior quahty, 

 analysis giving only of fixed carbon 71'4, and of volatile inflammable mat- 

 ter 13-3; the setting of the boiler required much alteration before snfticient 

 draught could be jirocurcd. The fuel was thrown on to the bars by hand, 

 which is the worst manner of using it, as from its density, and its being a 

 bad conductor of heat, it decrepitates when it tirst inflames, u.nless it is pre- 

 viously warmed — this was found to occur for a short time, but on the appli- 

 cation of the heated air the decrepitation ceased, and combustion went on 

 steadily. In ascertaining the amount of evaporation, the water at a tempe- 

 rature of ib was injected by hand from a vessel, the content of which was 

 measured, and the level in the boiler regulated by the float and index. The 

 fire was brought up to a certain intensity before commencing, and was left 

 in the same state at the end of the experiment; this mode of proceeding, 

 although objectionable with bituminous coal, is not so with anthracite, as it 

 does not swell during combustion so as to alter the bulk of the fire. 



Results of t/ie e.rperimeHt.— the Tcsnhs of an experiment exleiniing over 

 8 J hours without interruption, are then shown in a tabular forra. In this 

 trial, 448 lb. of anthracite were thrown on the fire in four equal portions, at 

 intervals of two hours; 3560 1b. of water at 45" were pumped into the 

 boiler and evaporated under a pressure of 17 lb. per square inch. .Aiter 

 deducting 40i lb. of unconsumed coal which fell through the bars, the 

 amount of evaporation was lound to be 8' 73 lb. of water for each pound of 

 coal consumed. If the feed water had been at a temperature of 212' the 

 evaporation would have amounted to 1003 lb. During this trial tlie air ia 

 the tubes of the boiler never exceeded 430°, but on subsequent occasions it 

 was raised as high as 700". 



This product of evaporation is below that obtained by other persons, 

 which the author attributes to the inferior quality of the specimens of an- 

 thracite, and the admission of cold air above the furnace bars when throwing 

 on the fuel, llis opinion is, that when anthracite is completely burned, the 

 practicil evaporative power will be found directly in proportion to the amount 

 of fixed carbon contained by it — that with the excejition of the loss of heat 

 which is always transmitted to the brick-work of the furnace, and of that 

 which is carried up the chimney to keep up the draught, the whole of that 

 evolved by the fixed carbon will be retained by the water; because from 

 good fuel there is little or no escape of gaseous matter, and hence the su- 

 perior efiicacy of anthracite. From the analysis of a number of specimens of 

 anthracite, the author found the quantity of fixed carbon to amount to 90 

 per cent. The evaporative power of these fuels, as fixed by Berthier's pro- 

 cess (la voie scche), would amount to 12'3 lb. of water for each pound of 

 coal consumed. He calculates that 6 lb. of anthracite will evaporate one 

 cubic foot of water under the ordinary circumstances of a steam engine 

 bailer, and taking the average specific gravity of bituminous fuel at 1280, 

 while that of anthracite is 1410, there is a dicTerence of nearly 10 per cent, 

 in favour of the latter, considering the space in which it can be stowed. 

 This is an important consideration for its use on board steam vessels, but it 

 is essential that its rate of combustion should be such as to raise steam 

 rapidly, its capabihties for which the author then proceeds to examine, and 

 deduces from the experiments that the combustion of the anthracite was 

 carried on so as to jiroduce a greater amount of evaporation in a given time, 

 than could be obtained fi'ora bituminous coal. This result is attributed in 

 some degree to the use of heated air. 



The author recommends that the anthracite should be supplied to the 

 furnace by a hopper through the boiler,* wherein it is warmed before reach- 

 ing the fire bars, which obviates the inconvenience of decrepitation, and 

 insures regularity in the supply of steam. 



Mr. Lowe saw no reason to doubt the results recorded by so accurate an 

 experimenter as Dr. Fyfe, which proved tliat anthracite was efficient just in 

 the proportion of the carbon it contained, bnt he was at a loss to reconcile 

 this with the opinion of Mr. C. W. Williams, who recommended the addition 

 of bituuiinous substances to pure carbon, as a means of increasing the calo- 

 rific power of fuel. He must repeat the oi)iiiion expressed by him on a for- 

 mer occasion, that the coal most free from elementary oxygen, would in 

 practice be found the most effective fuel. Neither could any fuel lie used 

 too dry or too hot. At the gas works under his charge, a considerable 

 economy had been effected by Mr. CroU's patent process of using the coke 

 as it was drawn from the retorts, and thrown in an incandescent state into 

 the furnaces, 



June 15. — The President in the Chair. 



The following were elected -. — Daniel Pinkney Hew ett and John Bou<tea(l 

 as Graduates ; and Gerrit Simons (of the Hague) as an Associate. 



" Description of the new Sewer in the Valley of the Cowyate, Edinburgh." 



By George Smith. 



In this coMmunication the author first gives an account of a complete sys- 

 tem of drainage, designed by him as architect to the Commissioners for 

 improving the City of Edinburgh, and then descrilies the mode of construct- 

 ing the first sewer, which begins at the south back of the Canongate. passes 

 along the Cowgate, and through the Grass-market to the foot of the Bow. 

 This principal sewer is 950 feet long ; it was built in several sections ; the 

 upper portion was 4 feet high by 2 feet G inches wide, and increased at the 

 lower extremity to 5 feet high by 3 feet wide ; it was constructed of stone 

 with vertical sides, and large flat stones for both the siUs and the covers — 

 the dimensions of tlie branch drains varied in proportion to the quantity of 

 matter passing through them; they were situated opposite the cross streets, 

 and had a cesspool to each, with a malleable iron grating hinged to afford 

 access for cleansing them. The average depth of the excavations was 9 feet ; 

 a great portion of the work demanded great precaution in executing, on ac- 

 count of the narrowness of the streets, the frequent floods, the local impedi- 

 ments from the gas pipes, &c., and the soft character of the ground, as in 

 some places the foundation stones sunk deep into the mossy soil by their 

 own weight ; it has, however, proved very successful, and will doubtless in- 

 duce an extension of the sewage of the City of Edinburgh, which has been 

 too long neglected. 



The paper was accompanied by two drawings of the construction of the 

 sewers, and the plan of the general system proposed, with the report to the 

 Commissiouers aud other explanatory documents. 



■' Plaver's Patent, 



