1849.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



315 



lain. A set of twelve dessert plates, celeste ground and gold, 

 with coloured convolvulus border, was beautifully drawn and 

 painted. 



Messrs. ^V'edgevvood had a few specimens of art in porcelain of a 

 high character. 



The stained glass exhibition we do not consider to possess merit 

 deserving of special remark. 



A curious series was a set of cotton stockings, manufactured 

 severally in 1700, 1716,1816, and 1817, shown by Messrs. Allen 

 and Solly, of Nnttingham, and bearing out the great progress of 

 the manufacture through Arkwright's exertions. 



Messrs. Newton and Son, of London, had a pair of thirty-inch 

 globes, a class of work for which the metropolis holds a very high 

 rank. 



The mathematical instruments we have before named. A glass 

 lens, 18 inches diameter; showed the resources of the glass-workers, 

 and the brass-finishing was of the highest quality. The lens was 

 by JNIessrs. Chance. 



Messrs. Chamberlain, of Worcester, had a choice display of por 

 celain, fully beai-ing out their established reputation. 



Messrs. Minton and Co. had likewise a large collection of equally 

 meritorious works in porcelain and parian, including above a hun- 

 dred articles. 



The glass collection of Messi-s. Richardson, of Wordsley, was 

 equally large. We may observe, that the glass collections showed 

 the great progress lately made in this manufacture. The shapes 

 of some of the vases and claret jugs had much taste; and the 

 colours and compositions in the Venetian and Bohemian styles 

 were equal to the best foreign works. 



The lamps, candelabra, and gas-fittings, by Messrs. Potts and 

 Winfield, were very good. 



JMessrs. G. R. Collis and Co. had an exhibition of their own, in- 

 cluding a great variety of articles in many branches of art, illus- 

 trating the resources of their celebrated establishment. 



The specimens of crystal glass, by Messrs. F. and C. Osier, in- 

 cluded a magnificent candelabrum, of the height of seventy feet, 

 and which was one of the wonders of the exhibition, realising the 

 fairy tales of the East, glittering, as it seemed, with gems and 

 colours. 



Messrs. Copeland displayed their accustomed merit in a choice 

 collection of objects in parian, porcelain, and earthenware. 



The silver, bronze, electro-plate, and or-molu of Messrs. Elking- 

 ton formed an exhibition, which merited and obtained the honour 

 of a separate catalogue. The presentation silver goods were mag- 

 nificent, both in design and workmanship. 



Messrs. Ilardman had a large show of church furniture and 

 fittings. 



The papier mache was by Messrs. Jennens and Bettridge, Ri- 

 chard Turley, M'Callum and Hodson, Frederick Walton, Thomas 

 Farmer, showing all the resources of Birmingham and Wolver- 

 hampton in this great manufacture. 



The cut glass by Messrs. Bacchus and Son, of Birmingham, and 

 the pressed glass, was in great quantity, and of high merit. Mr. 

 Rice Harris, of Birmingham, had another large collebtion, which 

 included some rich ruby tints. 



The collections of Messrs. John Rose and^Co., and of the Cut 

 Glass Company, showed no less beauty. Messrs. Lloyd and Sum- 

 merfield, of Birmingham, were also aiflong the meritorious exhi- 

 bitors of glass. 



Mr. Lane, of Birmingham, showed enamel, pearl, glass, and 

 papier mache. 



The bronzes of Messrs. Messenger were numerous and good. 



Nottingham and Coventry sent many specimens of their manu- 

 factures. 



Saddlery and saddlers' ironmongery being local trades, were 

 fully represented. 



There was a considerable collection of models and machines of 

 much interest to scientific men and the public. Messrs. Roberts, 

 of Manchester, were large contributors. 



Metal rolling and tubing are important arts, and were well illus- 

 trated. 



The glass water-pipes of Messrs. Coathupe and Co., of Nailsea, 

 were exhibited. 



The embossed horn buttons, by Ingram, are worthy of the high- 

 est commendation. It is wonderful to see the perfection to which 

 such articles are brought. 



On the whole, we can say this was an exhibition of very high 

 character; and although we have named many conti-ibutors, we 

 regret we ha^'e left out many of great merit. 



THE EXPANSIVE ACTION OF STEAM. 



On the Expansive Action of Steam, and a New Construction of Ex- 

 pansion Valves for Condensing Steam-Engines. By Mr. Fairbairn, 

 of Manchester. — (Paper read at the Institution of Mechanical 

 Engineers, Birmingham. 



The innumerable attempts that have been made to improve the 

 principle of the condensing steam-engine since the days of its cele- 

 brated inventor, A\'att, have almost all of them proved failures, 

 and have added little if anything to tlie claims, next to perfection, 

 of that ereat man's ideas. It would be idle to speculate upon the 

 various "forms and constructious from that time to the present, 

 which have been brought forward in aid of the original discovery 

 of condensation in a separate vessel. All that has been done is 

 neither more nor less than a confirmation of the sound views and 

 enlarged conceptions of the talented author of a machine which 

 has eiiected more revolutions and greater changes in the social 

 system than probably all the victories and all the conquests that 

 have been achieved since the first dawn of science upon civilised 

 life. 



It would be endless to trace the history of the successful and 

 the unsuccessful attempts at improvement, which for the last half 

 century have presented themselves for public approval; suffice it 

 to observe, that no improvement has been made upon the simple 

 principle of the steam-engine as left by Watt, and but few upon 

 its mechanism. Among t!ie latter may be enumerated the im- 

 provements in the construction and mode of working the valves; 

 and of these the D-valve by the late Mr. Murdock, and the use of 

 tappets, as applied to the "conical valves, appear the most promi- 

 nent and the most deserving of attention. 



In the construction of the parallel motion, the application pf 

 the crank, the governor, and the sun-and-planet motions, all of 

 which ha\e risen spontaneously from the mind of AVatt. there is 

 no improvement. Tlie ])rinciples upon which all of them are 

 founded have been rL'])eatedly verified beyonil the possibility of 

 doubt, and their mechanism is at once so exceedingly simple and 

 so ingeniously coatri\'ed as to limit every attempt at improvement 

 in those jiarts of the steam-engine. What appears to be the most 

 extraordinary part of Mr. M'att's engine is its perfect simplicity, 

 and the little he has left to be accomplished by his successors. 



It will be in the recollection of most persons conversant with 

 the steam-engine, that the hand gear for working the valves by 

 the air-pump or plug-rod, gave a self-acting and continuous 

 motion to tlie machine; and the facility which these means af- 

 forded for moving the engine in any direction and at any required 

 velocity, gave it a degree of docility and power beyond the expec- 

 tations of its most sanguine admirers. 



For a considerable length of time the hand gear was the best 

 and most eiiective mode' of applying the motion of the stean^- 

 engine to the valves; subsequently the oscillating and revolving 

 tappets, fixed upon a shaft and driven by wheels or an eccentric, 

 came into use, and by means of vertical rods communicated motion 

 to the valves, and thus a similar effect was produced as by the 

 hand gear; next came Mr. Murdock's U-valve and eccentric 

 motion, which for simplicitv Inis never yet been equalled. The D- 

 vahe, and the flat-plate \'al\e, are nearly synonymous— with this 

 difference only, that the D-valve presses with less force upon the 

 face, and consequently works easier than the flat-valve, which in 

 every case is exposed to the full pressure of steam. It is true 

 that 'means have been adopted to obviate this objection in large 

 engines, by a preparation on the back of the valve, which is made 

 steam-tiglit, and by a connnunication with the condenser, a vacuum 

 is formed over a proportionate area of surface, sufficient to equalise 

 the pressure and admit an easy motion of the valve. 



The expansive principle upon wliich steam-engines are now 

 worked, and the economy which this system has introduced in the 

 expenditure of fuel, has effected considerable changes in the work- 

 ing of the valves, and has rendered the D and plate valves almost 

 inadmissable for such a purpose. To the skill, ingenuity, and 

 careful attention of the Cornish engineers, we are indebted for 

 many of the improvements connected with the use and application 

 of expansive steam; and taking into account the high price of 

 coals, and the urgent necessity of economy in those districts, 

 which combined witli a system of registry and encouragement held 

 out by premiums as described by Mr. John Taylor, we may reason- 

 ably conclude that other parts of the kingdom have been greatly 

 benefitted by the excellent examples set before them by the Cornish 

 miners and engineers. 



For a great number of years, and up to a recent period, tne 

 economy of steam and the'working of the steam-engine expan- 

 siiely, were but imperfectly understood in the manufacturing dis- 



41* 



