44 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



street'already indicates our correspondent's predictions ; hut the bad 

 success of the experiment is not to be attributed to defects inherent in 

 that kind of pavement, but to the unwarrantably careless manner in 

 which it has been laid down ; another cause of its failure may be 

 attributed to the small space allotted for the experiment, the mud from 

 the roadway at each end is brought on to it by the horses' feet and 

 carriage-wheels, which keeps it constantly covered with mud or dust 

 as the other 'pavement, whereas tlie great cleanliness of a wooden 

 pavement is one of its prominent advantages, which can only be secured 

 by having it for some distance.] 



WHEELS OF LOCOMOTIVE ENGINES. 



Sir, — I beg to submit to the consideration of the readers of your in- 

 fluential Journal, a suggestion on the construction of the wlieelsof loco- 

 motive engines, should you consider it of sufficient value to be admitted 

 to your pages. It is simply to call attention to the feasibility and utility 

 of employing brass as the material forthose parts of the engine. Weweil 

 know that in machinery generally, it is considered of great saving in wear 

 and tear to prevent thecoataet of kindred metals, and perhaps it might be 

 deserving of consideration how far the wear of the rails might be 

 lessened by such an expedient. 



Anything tending to promote this object I know will meet with 

 attention; and it might perhaps be practicable by the use of brass 

 wheels to save the expenditure of metal on the length of rails which 

 are more difficult to repair, and therefore more expensive. I do not 

 pretend to decide upon the utility of this suggestion or its actu.al 

 economy in working, but perhaps some of your leaders who are en- 

 gaged in experiments on railways and have the means of trying it, 

 might be induced to ascertain what would be the practical result. 



In machinery, as you know, the contact of homogeneous metals is 

 sometimes prevented by the application of leather, but it would be 

 absurd to propose such an expedient for adoption on a railway on a 

 large scale. It might, however, be well worth experiment on a small 

 scale, as elucidatory the laws of friction, how far the application of 

 leather or other substance to the wheels or rails, by producing a smoother 

 surface, would be caliMilated to diminish the friction. 



I am, sir, yours, &c., 



■ HYDE CLARKE, C.E. 



STUART'S DICTIONARY. 



Sir — 111 the last iiuniTier ofyour u.^eful Journal your correspondent, 

 " A Constant Header," while noticing Mr. Britton'.s Biclionary of 

 Ancient Architeclure, adverts to the deticieneies of preceding similar 

 works; and, among others, he names '• Stuart's Dictionary of Archi- 

 tecture." Having had the misfortiuie of projecting that compilation, 

 I am desirous of your permission to ^-ay a few words in explanation of 

 .«o»(e of its manifold imperfections. 



It was originally designed to eonlain a ycnerul collection of tech- 

 nical architectural terms, a popular history' of the arl in all countries, 

 and biograidiical notices of archil eels ; but the eugagenicnls of the 

 publishers, urging a greater haste in publication tlian was consistent 

 with a careful preparation of the manuscript, I found it inipractica- 

 l)lc, under the circumslanees, to carry out the design fo my own 

 satisfaction. The labour of crude and undigested compilation became 

 so irksome, that after hurrying a fi:ir of the first sheds through the 

 press, and preparing about twenty-live of (he engravings, 1 was glad 

 to resign my share of the speculaiion. Feeling, however, the weight 

 of my own faults, I was imwilliug to ran the ri.sk of being loaded, in 

 addition, with the editorial sins that niighl possibly be co'lumitted by 

 my successor, and I tliercfore stipulated Ihat the name of another 

 Editor should be substituted for nunc in the future parts of (he com- 

 pilation. Some time after this the publi^hel•s became Iiaukrupt, and 

 1 thought the book had deservedly died, as it '• made no sign." The 

 IcKer of your correspondent first informed me dial it had subse- 

 quently been revived, and eonliuued, and Ihat (oo under (he original 

 title. A peep, a few days ago, into the Iruly '■ finished" Dictionary 

 of Architecture, by Koljert S(uar(, makes nie anxious (o assure the 

 '• Constant Reader" that I am uKcrly innocent of niuetcen-twenticths 

 of its nonsense and plagiarisms. Sliould any of his friends be sim- 

 pletons enough to buy the volumes, in the liope of linding that kind 

 of inforniHtiou which the title pages say (hey eonlain, and in (he bit- 

 terness of di.sappoinlmeut, proceed fnmi damning the book to i)crforiu 

 the same duty towards its authors, I eulreat (he " Constant Reader" 

 to interpose his friendly offices, and direct tliat ouc-tweuticth part 

 only, and no more, of the deserved lualedictions shall res( on mv 

 devoted head in time coming. I am sure he will feel the reasonable- 

 ness and justice of my reiiucst, when he reflects that for several vears 



past I have, unknown to myself, borne all the blame of compiling 

 that miserable production. 1 am, sir, your obedient servant, 



ROBERT STUART. 

 London, 22d Jan. 1839. 



ON ARCHES BUILT IN CEMENT. 



The custom of turning arches in cement has now become very 

 general with engineers, more particularly where great strength is 

 required, as culverts under heavy embankments, and arches of a flat 

 elliptical form. It appears questionable whether the additional strength 

 acquired by turning arches in cement is leal or imaginary ; taking into 

 account the great liability to fracture in all brick structures built in 

 cement, the least settlement occasions a fracture, by which the adhe- 

 rence of the cement to the brick is totally destroyed, "but which would 

 not be the case did the cement possess any yielding properties, as 

 common mortar. 



In some cases I have observed arches turned in mortar, and a few 

 feet at the crown only built in cement; and again elliptical arches 

 built in mortar as high as the haunches, and the remainder in cement ; 

 this latter method will doubdess allow the arch to settle in a slight 

 degree without detriment, in which case it would merely have the effect 

 of forcing out some poilion of the mortar joints ; that part in cement 

 remaining a compact mass, any rupture in which would occasion its 

 destruction. A slight percussive force will often have the effect of 

 rupturing a wall in cement, which would be comparatively harmless if 

 built in mortar. 



It has often occurred to me, and I now respectfully submit it to the 

 notice of engineeis, whether in the case of an arcli being turned in 

 cement, it would not be preferable to have mortar joints in each ring 

 running quite through the arch, which I suppose would allow of some 

 considerable settlement to take place without injury to the structure : — 

 say in the case of a brick arch having three or more courses in tlie first 

 half brick ring turned in cement, and as many courses in the remaining 

 rings as necessary to allow of a continuous mortar joint from the 

 soffit to the back of the arch. The part in cement assimilating to a 

 string course in masonry. I imagine that this method of construction 

 would possess many advantages over that in present use — especially 

 where there would be reason to suspect a subsidence of the abutments. 



PETER BUUFF. 

 Charlotte Street, Bloomsbnry, 

 January -iOth. 



BENNETT'S NEW STEAM ENGINE, 



FOR CAPT.MN COBl'S STEAMER. 



We make the foUowinj extract from a pamphlet, forwarded to us from Ame- 

 rica, entitled " Allanlic Stenm S/iips" : — 



This vessel, built under the immediate superintendence of C'.iptniii Nathan 

 Cobb, and intended for the Liverpool trade, is now completed, and will be 

 ready for her first voyau^c across the Atlantic on the lOth of June (1838).* 



This enterprise was planned and decided upon by Captain Cobh (then of 

 tlie Liverpool packet Columbus) in 1834. Ho memorialized the legislature on 

 the subject, without success ; but, determined to test its practicability, he en- 

 tered into a contract with Mr. Phineas licnnott, of Ithaca, to supply the 

 machinery for his intended vessel before the 1,5th November, 18;3G. Various 

 delays, however, occurred in performing the same — the engine being con- 

 structed on a principle entirely new, the sole invention of Mr. Bennett ; but, 

 had the contract been duly fulfilled. Captain Co'^b's vessel, having been built 

 upwards of two years, would doubtless have reached the English docks several 

 months before (he first voyage of the Sirius to this country. 



Presuming the annexed description of her engine will interest many ef our 

 readers, we copy it entire : — 



This engine has undergone the scrutiny of great numbers of scientific pro- 

 fessors, ingenious and experienced loechanics and engineers, citizens and stran- 

 gers ; and the examinations have resulted in a general convictiun that the 

 world is about to realize a new improtcmeiit, not inferior to that of Walt and 

 Holton — an improvement that will effect a new era in ocean navigation, and 

 bring all parts of the world in approxiniaiiou to each other. A voyajje to 

 Liverpool, it is btlicvod, may, by the power of this engine, be accomplished in 

 ten days, and with only uiie linllt of the fuel heretofore required, thereby 

 allowing more room for passengers and freight. 



The following descrijition and drawing, it is hoped, will fully explain liow the 

 fire and the water can be brought and continued in actual contact with each 

 other, and, rapidly generating tbe steam, sliil kept in controul, and iti potency 

 safely directed to piopel the ship, or utlicr object to which it may be a|)plied. 



The engine for Captain Ccbb's Liverpojl steam-packet, is a double hori- 

 zontal high-pressure engine, thirty-five inch cylinder, and six ieet stroke, with 

 two blowing cylinders, of half ihj capacity, worked by the piston-rod of the 

 stcom cylinder passing' through the loner or extreme head, and into the blo« ing 

 cylinders; consequently, both will be of the same motion. 



* \\'c luivc not jct received anv iutelli-icnce i.l tlii.-. vcsatl having been CQmptefcd uj 

 ready lot her intcu'ltil \ oyafc.— Bn. C. E. & A, Jovr, 



