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THE CIVIL ENGINEER AND ARCHITECTS JOURNAL 



[April, 



has rarely been accomplished. A peculiar feature of these communications, 

 anil one to which the council would particularly advert, is, that they are not 

 of a speculative character, but present a lietailed analysis of authenticated 

 facts. 



This analysis consists in separating and ascertaining the various results, 

 and in referring tliem to particular classes, so that they may he readily appli- 

 cable in practice. The merit of instituting and recording a series of obser- 

 vations upon a scientific subject is universally acknowledged, but the reduc- 

 tion of such observations so .is to form a standard of reference to which the 

 practical engineer may appeal, is a task of far greater difficulty, and its exe- 

 cution of far higher merit. It is in this eminent rank thit the council would 

 place these communications of Mr. I'arkcs. 



The description by Mr. Leslie of the Harbour and Docks of Dundee, was 

 also briefly ad\erted to in the last annual report, as one of those communi- 

 cations on which the Institution sets great value. It consists of a detiiiled 

 account of the progress of tlie improvements jjrojected by Smeaton, Telford, 

 and others, in part carried into execution by the projectors, and completed 

 inider the author's own superintendence since 18.''2. The illustrations of the 

 projected and executed improvements with the plans, elevations, sections, 

 and details of the works of the docks, gates, quays, craqes, and machinery 

 employed, occupy 30 sheets of drawings. To the copious history and de- 

 scription of these works is added an extensive scries of observations on the 

 tides. The determination of these facts for different parts of the globe, is a 

 question of the greatest importance in physical astronomy, and the council 

 would take this opportunity of jiointiii!; out the essential service which may 

 thus he rendered by the engineer to the cause of science by his lecording the 

 observations which /le has pre-eminently the opportunity of making. For 

 this valuable record of an executed work, the council have awarded a silver 

 n.eclal, and a copy of the hfe and works of Telford. 



.\ silver medal and the life and works of Telford have been awarded to 

 your associate, Robert Mallet, for his communication on the " Corrosion of 

 Cast and Wrought Iron in Water." This communication presents features 

 of no ordinary interest to the engineer. The comparatively recent intro- 

 duction of cast iron for the purpose of piling, for wharfs, &c., and of wrought 

 iron in the construction of vessels, has rendered the subject of the action of 

 water upon iron of peciUiar importance; the British Association have, from 

 time to time, granted sums of money for making experiments on this subject, 

 and ,\Ir. Mallet having been engaged in conducting these experiments, has 

 selected from the very extensive series of results obtained by him, those con- 

 clusions which may be of service to the practical engineer. The most valu- 

 able portion of this communication consists of elaborate tables, which exhibit 

 ihe results of the action of clear and foul sea and fresh water at different 

 temperatures upon cast and wrought iron. Such being the general nature 

 of the experiments, the results to which they lead, or the effects produced, 

 present several remarkable characteristics, and it is found that the corrosive 

 action of water and air combined, produces, on the surface of cast or wrought 

 iron, a state of rust possessing one of five distinctive features, viz. uniform — 

 uniform with plumbago — local — local pitted — tubercular; or some two or 

 more of these in partial combination. The practical results which may be 

 deduced from these tables are of the highest value to the engineer, and point 

 to considerations of the greatest importance ; thus the upper and lower strata 

 of water, of different degrees of saltness and density, coming in contact with 

 the same mass of iron, a voltaic pile of one solid and two fluid elements is 

 formed, and under such circumstances the corrosive action is materially aug- 

 mented ; hence it follows as a practical conclusion, that the lower part of all 

 castings used in such situations, should be of increased dimensions. Similar 

 residts, the knowledge of which is of great importance to the practical engi- 

 ncer, such as the rapid decay of iron in the sewage of large cities, of the bolts 

 of marine engines exposed to the bilge water, and of boilers containing hot 

 sea water, are referred to actions due to similar physical principles. The 

 protection which metals receive from paint, or from the presence of various 

 alloys, so as to obtain a mode of electro-chemical protection, such that, while 

 the metal iron shall be preserved, the protector shall not be acted upon, is 

 also referred to >iriiil:ir principles. 



The couTitil have also awarded a bronze medal and books to Mr. Charles 

 lloimis, for his comnuinieation on "setting out railway curves;" to Mr. 

 Chapman, fur his description and drawings of " a machine for describing the 

 profile of a road," and to Mr. Henry Kenton, for his description and drawing 

 of "a self-acting Waste-board on the River Ouse."' 



The communication by Mr. liourns is an application of simple geometry, 

 leaiiing to practical results. In setting out curves recourse has been had to 

 various expedients, but Mr. Bourns, in the propositions contained in this 

 pa;ier, has shown that, by the use of the common chain, an ofl'set staff, and 

 faille of otl'sets, he is enabled to set out curves of any radius and flexure, 

 with a facility and precision not generally attained. 



The description and drawings of a machine for describing the profile of a 

 road, is one of several communications on this subject, sent in accordance 

 with the notice of subjects for competition issued by the council. Many of 

 the arrangements proposed by the author exhibit considerable ingenuity, and 

 though difficulties may exist in their practical application, the council think 

 this attempt may be of assistance to others, who may have their attention 

 directed to the construction of an instrument for similar purposes. 



The description and drawing of the self-acting waste-board on the river 

 Ouse, being an account of an executed work, is one of those communications 

 which the council are most anxious to encourage by every means in their 



power. The drawing and description fumisbeii by Mr. Renton are highly 

 creditable to the talents of the author, and deserving of some si)ecial mark 

 of approbation. 



The council have also awarded hooks to the value of five guineas to Eu- 

 genius Birch, for his drawing and description of the machine for sewing flat 

 ropes, in use at lluddart's rope manufactory. The rope macbincn. of Cap- 

 tain Iluddart was, some time since, one of the subjects on which the council 

 solicited communications ; on that occasion two valuable sets of drawings 

 were communicated, the one by Mr. Dempsey, the other by Mr. Birch. The 

 subject of the present communication was not included in either of the pre- 

 ceding, but Mr. Birch, desin.us of availing himself to the fullest extent of 

 the liberality of Mr. Cotton, the then proprietor of tlie machinery, and of 

 carrying out the views of the council, has devoted much time and labour to 

 ]j|aiing in the Institution, an exact record of everything connected with this 

 interesting machinery. 



Premiums of books have also been awarded to Mr. Maude, for his " Ac- 

 count of the Hepairs and .^Iterations made in the construction of the Menai 

 Bridge, rendered necessary by the gale of January 7, 1839," .-lud to Mr. 

 Andrew Bum, for his drawings of a •' Proposed Suspension Bridge over the 

 Haslar Lake." The council would point out these instances of the fulfilment 

 of the engagements entered into on election, to the attention of the other 

 graduates of the Institution, who have similar opportunities, but who have 

 not hitherto kept their promises. It is the dnsire of the council to obtain an 

 exact record of works that are projected or in progress, and such records are 

 peculiarly adapted to compete for the Telford ]iremiums ; Mr. Maude and 

 Mr. Burn, with iiroper permission, have availed themselves of the facilities 

 afforded them, and the council trust that the premiums now awarded, and 

 the marks of approbation here expressed, will stimulate others to avail them- 

 selves of like opiiortunities. The authors of such communications will thus 

 most materially contribute towards promoting the interests of the Institution, 

 and to their own qualification for future employment and advancement in the 

 profession. 



The Institution has received during the past year, many other communi- 

 cations of acknowledged merit, of which no mention has yet been made. To 

 a few of them the council would now briefly advert, and especially to the 

 last paper by Mr. Parkes, " On the action of Steam in the Cornish Single 

 Pumping Engine," a communication of no ordinary importance and interest, 

 either on account of its own intrinsic merits, as viewed in connexion with 

 the past proceedings of this Institution, or the future pospects of this depart- 

 ment of practical science. This communicatioQ, though intimately connected 

 with those of the same author previously alluded to, growing immediately 

 out of them, and depending upon the facts contained in them, is of a totally 

 distinct character ; being an attempt to explain, on theoretical principlei, 

 the action of the steam on the piston, and to unfold the real causes of the 

 economy of the Cornish engines. This subject has occupied the attention of 

 the Institution during the last four years, and the discussion first assumed 

 a settled form during the session of 1837, on the receipt of the communi- 

 cation of Mr. George Itolworthy Palmer, "On the application of Steam as 

 a moving power, especially with reference to the reported duties of the 

 Cornish and other Engines." In that paper the author, reasoning on certain 

 data as to evaporation, and on the physical facts which involved the con- 

 stancy of the sum of the latent and sensible heat in steam of ail elasticities, 

 and of the absorption of heat by matter on dilatation, came to the conclusion 

 that no power could be gained by expansive working, and that, consequently, 

 this could not be the cause of the economy in Cornish engines. This dis- 

 cussion was revived in the ensuing session by the communications of Mr, 

 Wicksteed and Mr. Henwood, the former furnishing the first recorded expe- 

 riment in which the water raised was actually weighed, the latter giving an 

 extended series of most careful and detailed observations on the quantity of 

 steam employed, the mode of its distribution, the duty performed by a given 

 quantity of fuel, and the measurement of the water raised. 



Taking for data the facts furnished by Mr. Henwood for the ViTieal Towan, 

 and by Sir. West for the Eowcy Consols Engines, Jlr. Parkes Las analyzed 

 the quantity of action obtainable from the quantity of water as steam con- 

 sumed, and expanded to the extent used in those engines, and lias found the 

 steam's force unequal to the resistance overcome, .^fter satisfying himself 

 from various phenomena attendant on the working of these engines, that the 

 amount of resistance opposed to the steam was not overrated, lie was led to 

 conclude that from the instantaneous and free eoniuiunication eft'ected be- 

 tween the cylinder and boiler of these engines, by the sudden opening of the 

 large steam valves, a force must be transmitted to the piston, of a kind dis- 

 tinct from that of the steam's simple elasticity. This force be denominates 

 the steam's ^erciusM'e action ; be adduces various proofs that this description 

 of force has operated on the piston, and that it alone was equivalent, in the 

 instance of the Fowey Consols Engine, to drive the piston through -j^jths of 

 its stroke. 



The author considers the effect produced on the piston of a Cornish En- 

 gine, by the sudden impact of highly clastic steam, to be similar to that ob- 

 tained from water in the hydraulic ram. He has not iu his paper entered on 

 the consideration of the absolute amount of percussive force, which can be 

 afforded by an aeriform fluid in motion — but has cuufiued himself to the de- 

 termination of the quantity of action, which he conceives to have been de- 

 riveil from that source in the particular engines examined. He invites the 

 co-operation of others in instituting experiments on this subject, and the 

 Council hope that the ensuing Session will augment the number of facts re- 



