I'M 



THE CIVIL i-N(jinI'I:k \m) aiu'ihtkc is journal. 



[A PR II 



closed llicsc juiiits, .iml oiicricd those at the erowns. Thus the joints (if the 

 parapets, which were inaile of shiglc slabs of granite for tlic whole heislit, 

 Ijecame good indicators of the changes of tenipeniture. li had also heen oh- 

 served, in tin: Waterloo and other bridges, that joints made good in the 

 winter witli Itonian cement were found erushed in summer. 



Viththe view of obtaining some data for ealcuhition, .\Ir. Rcnnie jirocured 

 saniples of granites sandstone, and slate, and plaeijig thoni in a properly con- 

 strnrtcd oven, ascertained the rates of tlicir expansion, which are given in 

 the paper. 



A series of cxjierimcnls was made at the rc(piest of the late Mr. Kcnnie by 

 Mr. S. Walker, of Uolhcrham, on the variations iji tlie length of 231 .?. feet of 

 the frieze, bolted together and laid on a firm platform. The (euj]ifriiturc of 

 the atmosphere and of the plales and tlie length were noteil at live o'clock in 

 the morning and at three o'clock in the afternoon, and in some of llie ex- 

 periments at se\cu o'clock in the evening. The details of these cxiicriaicnis 

 are given in tlic jiaper. 



The paper is accomjiauied by calculations for the rise of an arch and the 

 opening at the sjiandrils for an increased tcnii)crature, and also by tables of 

 the cxpansibihly of different kinds of stones and irons given by Distigny. 



" S/jcriJicnIioii. mill IJ'urkiny Drnmnys nf the MhUUexhurough-OH-Tees Oas 

 Works." By PuTKR IIendkuson, Assoc. Inst. C. £. 



in this communication, the author details the several works, erections, and 

 fittings of tlie (ias Works at Middlesborongh-ou-Tecs, and the mode in which 

 they are to be executed aud coni]ilcted. 



•' On a Hioi/e »/' IJnireUing Timber, or of t-ombinmii il and olUer ma/eriuLs 

 for geiieral jmrpoxes." IJy M. J. Buunei., M. Inst. C. E. 



The author proposes to unite timber by means of iron dowels and asphaltc. 

 Mastic had been used in the Tunnel works for the purpose of tilting small 

 plates of cast iron to the poling boards. These, thongli eonslanlty immersed 

 in water and nmd, and snhjeet to severe hammering, bad .stood perfictly well. 

 Asiihaltc is now used in preference to mastic, as it sets immediately. The 

 author conceives that stone maybe united by a simitar kind of dowelling ; 

 anil that wood ni.ay be iiiter)iosed between stone and iron, so as to be used 

 to advantage with the stone blocks, for the chairs of railways. Also, that 

 this method may be used with great advantage in sliip-buihling, in mast- 

 making, ami wherever any species of doweUing is refiuired. 

 Feb. 21. The President in the Chair. 



" On Steam Ungincs, principally with reference to ilietr coiinuuijitinn uf 

 Steam and Fuel.' IJy Josiah Parkks, M. Inst. ( . E. 



The above is the second and concluding comniunication on this sniyect ; in 

 the former, the generation of steam more particuliirly was considered; in the 

 present, its aiiplicalioii when generated. These are distinct qneslions, as it 

 is the economy of steam which constitutes the dynamic perfection of a steam 

 engine, whereas it is the economy of heat in supplying tlmt steam which con- 

 stitutes the jicrfcction of the boiler as an evaporati\c vessel. These economic 

 properties are totally inde|)endent of each other; they may co-exist in a 

 inaxinimn degree, or in very diflerent degrees, aud the degree of perfection 

 which any particular class of engines, or which the particular engines of any 

 class possess, is known from the weight of fuel Liirnt, of water evaporated, 

 and the mechanical etlcet realized. As long as engines were constructed with 

 but few varieties, or identical in their forms, the |)crformance of one was a 

 sulficieiit indication of the performance of all ; but new forms of engines and 

 new modes of practice being now introduced, a comiiarison of the iierfonn- 

 ance on the several systems is a matter of deep iiraetieal ami scicntilic in- 

 terest. Mitli the view of effecting this object, the author has collected all 

 the authentic facts within bis reach, aud reduced llicni to common standards 

 of comparison. 



The elleetivc power of steam engines may be aseerlained cither from (he 

 resistance overcome, or from the load upon the jiLston i>y means of the indi- 

 cator ; the former method being ajiplicable to ]iumiiing, the latter to rotative 

 engines. Cut the eU'eelive power of the steam in lunuping engines, as thus 

 ascertained, is far below the real eiteetive power of the steam, ami no exai;t 

 comparison can be made by these means between the clFeetive i«i\ver of the 

 steam in the two classes of engines. The useful clVect is not synonymous 

 >vitli a true measure of eU'ective jiower, since tlic duty is the true useful eU'eet 

 in a Cornish engine. The indicator when applied to liiu Cornish engines en- 

 ables us to ascertain the absolnle but not the efi'ectivc power, so as to com- 

 pare it with (hat of the rolative engine, since the friction of the engine and 

 the load cannot be scpar;itely determined. The absolule power of the steam 

 may also be ascertained from the relative knowledge of the clastic force of 

 steam corresponding with the r.atio which the volumes of water bear to each 

 other. This theoretical estimate rcipiircs however several corrections ; among 

 ■which (he steam condensed by contact with colder surfaces, the steam con- 

 sumed in filling useless' places, and that lost by priming, must he jiarticularly 

 noted. 



The relative performance of pumping engines is well expressed by the term 

 "duty," that is, the iinmbcr of llis. raised one ftnit by a given quantity of 

 fuel ; and of rotative engiues by the term "horse iniwcr," that is, the num- 

 ber of Ills, raised one foot in a minute, divided by .''o,0U0 lbs. the standard 

 measure of a horse. The perforniauce of the rotative engine may also be 

 estimated by duly, and of pnmiiing engines by horse power. The results of 

 these computations for several engines are tabulated in this communication. 



The sum of the latent and seusible heat beiug coustaut for tsteam of all 



elasticities, the expcniliture of both power anil heal is truly ineaMired by the 

 weight of water consumed as steam ; this measure is free from all uncertainty, 

 and independent of all (bi'ory ; the weight of w.ater as steam cipiivalent to 

 the production of a bor.-c power in each engine, .•iiid the duty effected by one 

 poiiml of steam, will denote the positive and relative eniciency of the steam 

 and the heat. These indices of etficieney being referred to some standard, 

 wc learn, from the preceding data, the precise value of each engine in its use 

 of steam and fuel ; of its boiling aiiimratus, as a generator of steam ; of the 

 com)),irative efficiency of the steam and coal, or economy of jiower and fuel. 

 The results which may thus be obtained are also exhibited in tables, accom- 

 jianying the eommuuieatiou. 



Tlie jiower resulting from the expenditure of ei|iial weights of water, as 

 ste.on, being known, the boiler may be connected with the engiues, and the 

 rcl.itivc extent of heating surface employed to fnruisb their power shown. It 

 will thus appear that equal measures of surface arc (piitc inadequate to supply 

 cijiial power, with equal economy, to dificrcut classes of engines. These re- 

 sults arc tabulated in great detail, and it ajijicars tli.at the Cornish engineers 

 now eiiqiloy nearly eight times as much boiler surface for equal nominal 

 power as (hat given by M att's practice. Hut taking into account (be fuel 

 burnt per horse power ]ier hour in the two cases — the Cornish engine con- 

 suniing 'ij llis. jier horse power per hour, and Watt's engine H.l — the true 

 relation of the Imilers is as 19 to I. Many other relations of a similar strik- 

 ing character may be deduced from these tables. 



The detailed results of the experiments by Smeaton in 1772, on his im- 

 pioveil Newcomen engine at Long Ueiiton — li_\ Watt, in 1 7H(), on hisiolalive 

 condensing engine, at the Albion Mills, arc recorded in these (ables; and it 

 appears that the economy of the latter as regards steam and fuel was double 

 (bat of the former, and ajiproached very nearly to jierfeetion in the use of 

 power obtainable on that principle. The next great advance in the economy 

 of fuel and |)ow ei is (hat made by the Cornish engineers, whose performanrcs, 

 both with puinping ami rotative expansive engines, far exceed any attained 

 with the common uncxjiansive condensing engine. The superiority of (woof 

 these engines in ly.'io, doing a duty of HO millions, exceeds the engines of 

 Watt and Neweomeu by 21 aud 5 times in economy of power, and by 3^ and 

 7 times in economy of fuel. 



The obtaining a standard measure of duty is of great inipor(aiiee ; ahe.apcd 

 measure, as a bushel of coals, is highly ohjcetionahle, as the weight of such 

 measure will vary from 84 to 112 lbs. In the Cornish re|)orts the bushel is 

 fixed at '.M lbs. weight, as the standard of eoni])aiison, hut some iiortiou of a 

 ton or one lb. would be a better slaiKhird. (It her condmstililes, how^ever, as 

 coke, peat, &c., may be used partially, or to (he exclusion of coal, and under 

 these eircnmstances some other stamlard of coiii)>arisoii is necessary, and wilh 

 this view (he author suggests a pound of water in the form of steam as tlie 

 best standard of duty. The work done by a given quantity of water .as steam 

 is a sure index of the quality of the steam engine ; it is a measure unctieeted 

 by Miri.able eaJoririe agents, .and so long as engines continue (o be worked by 

 steam, so long will the performance of different engines be aeeurately ganged 

 by their respective expenditure of water as steam. The acenracy of this mea- 

 sure depends on the physical fact of the eonstaney of the latent and sensible 

 heat in steam of all tcmperatm'es. The author has recordeil twenly-eiglit 

 experiments made on twenty-eight ditferent ilays, on vaporization from the 

 boiling point to 60 lbs. pressure above the atmosphere, which ]n'eseiit a re- 

 markable connrmation of tlie above law, and show (hat (he relative clheieney 

 of steam in engines is due to the manner of using it, and not 1(^ any change 

 in its chemical constitution at different pressures. The manner of eondiieting 

 these exi>eriiiiciits, and the precautions taken to ensure accurate results, are 

 detailed with great minuteness. 



The .author next proceeds to tre.at of the Locomotive Engine, and to dis- 

 cuss, compare and taluilatc the facts relating to this engine in the same man- 

 ner as he has done those of the stationary class. The qualities of the boiler 

 of the locomotive as an evaporative vessel had been discussed in the first 

 coniniunic'ition. The locomotive dift'ers from the fixed non-condensing en- 

 gine only ill the use of the blast, and the same method of measuring the eficets 

 of the sAeam are applicable to both, l-^xiierimenters on the locomotive have 

 generally attempted to determine the amount of resistauce oiqiosed to its 

 progress in preference to ascertaining the power expended in overcoming the 

 resistance. The exact solution of either of these questions would furnish all 

 that is wanted ; but the ascertaining the total resistance by an aiiah sis of its 

 several constituents is attended with great difficulties, as the forces to which 

 they are to be referred are so exceedingly iiumerous and variable, (hat the 

 assigning the exact value to each at any one velocity has hitherto eluded the 

 talents of those who have pursued this method. M. de Pambour was the first 

 analyst whose labours will require attention. The tesnits given by this author 

 iu his practical treatise on Locomotive Engines on Railways were compared 

 by Mr. Parkes with the results which he bad obtained when experimenting 

 on an engine of precisely a similar character, and discrepancies presented 

 themselves which appeared totally irreconcilable. These and other circum- 

 stances led the author to consider, whether the resistance to traction would 

 proiierly be deduced from the laws of gravitation, or whether any certain re- 

 sults would be derived as to the amount of resistance on a level from obser- 

 vations on engines and trains moving down inclined planes. The great object 

 seemed to be to discover some criterion of the mechanical effect produced by 

 a locomotive at all velocities, which would apply as practically and as dis- 

 tinctly to a locomotive as duty to a pumping engine, or horse power to a 

 rotatory engine. If this were possible, it seems of far less importance to 



