IS4I.1 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



50 



DESCRIPTION OF THE ENGINES ON BOARD THE "GOR- 

 GON" AND "CYCLOPS" STEAM FRIGATES. 



For the following description we are indebted to Mr. John Sea- 

 ward's pamphlet, from which we have already quoted the two excel- 

 lent papers "On Long and Short Stroke Engines," and "Long and 

 Short Connecting Rods," published in our last volume ; and for the 

 engravings we are indebted to the Miclianic's Magazhie. 



The steam engines which have been supplied by Messrs. John and 

 Samuel Seaward and Capel to the British steam frigates Gorgon and 

 Cyclops, and to several other large Government steamers, are con- 

 structed upon a plan ditlering materially from those which have 

 hitherto been mostly nsed in steam navigation ; they have been de- 

 nominated "The Gorgon Engines," from the fact of a pair on this 

 plan having been first tried on board the steam frigate of that name. 



These engines are constructed on the principle of what is called 

 the " direct action," that is to say, the power of the engines is com- 

 municated from the piston by the piston rod, direct to the crank, with- 

 out the intervention of those side levers or beams, cross heads, fork 

 lieads, and side rods, which are usually employed in the construction 

 of marine engines. The engravings, one being a side view, and the 

 other an end view, will give a tolerable idea of the arrangement of 

 these engines : 



A is tlie cylinder; B the piston rod; C the main shaft; D the 

 crank ; E the connecting rod, which connects the top of the piston 

 rod to the pin of the crank. 



The top of the piston rod is constrained to move up and down in a 

 perfectly straight vertical line, by tlie aid of a peculiarly constructed 

 parallel motion. The bar or lever F is jointed to the cap of the piston 

 rod at G, and it also turns or oscillates on the joint or bearing H, which 

 joint or bearing is supported by the rocking standard I; the bar or 

 lever F is retained by a pair of rods K, which are jointed at one end 

 L to the bar or lever F, and at the other end to the fixed centre M. 



N is the air pump, which is worked by means of the pair of side 

 rods O, which are attached to a prolongation P of the aforesaid bar or 

 lever. 



It will be observed that the distinctive features of these engines 

 are, first, the line of shafts being placed directly over the centre of 

 the cylinders; and, second, the power being communicated direct to 

 the crank without the aid of beams, cross heads, side rods, &c., as 

 before stated. 



The line of shafts rests upon strong frames, which are supported 

 by wrought iron columns, standing upon the top of the cylinders; so 

 that the whole force of the engines is confined between the cylinders 

 and the supporting frames and columns, and does not act against any 

 part of the vessel. 



It should be observed that many engines have been constructed, 

 previous to the Gorgon engines, upon the principle of the " direct 

 action," but the arrangements of all those engines have been widely 

 difierent. 



The advantages of the present system are very considerable, and 

 consist of: — 



1st. ^ Great Sari:ig 0/ Space. — A pair of Gorgon engines do not 

 occupy much more than one half the space required for a pair of beam 

 engines of the usual construction. 



2nd. ^ Great Saving of Weight. — The weight of a pair of Gorgon 

 engines is "25 per cent, less than that of a pair of beam engines. 



3rd. Greater Exemption from .Occident, — The simplicity of the 

 arrangements, and the reduced number of moving parts, necessarily 

 lessen the chance of accident, as also the wear and tear. 



4th. Greater Security for the Engine-men who work the Engine. — 

 There being no side levers or beams in movement, the men can move 

 round the engines in every part with perfect safety ; but they cannot 

 do so with beam engines without much danger. 



5th. The Tremor and Vibration usually experienced in Steam Vessels 

 are almost entirely prevented. — The chief cause of the tremor and vi- 

 bration observable in steam vessels, is the pumping action of the 

 beams or side levers, which causes a great strain and effort throughout 

 the whole vessel ; but there is nothing of this in the Gorgon engines. 



6th. ^'i more efficient and economical .Application of the Motive Power, 

 —resulting from the absence of a large mass of moving matter, and of 

 many joints and bearings, the latter of which especially, is in ordinary 

 engines the cause of 7nuch loss of power. 



The advantages above enumerated will, for the most part, be very 

 obvious, on even a slight examination, by any impartial and competent 

 judge ; and of the great importance of the advantages themselves, no 

 one will pretend to doubt for a moment. Indeed, as regards the suc- 

 cessful application of this system, the matter is now placed beyond all 

 dispute, as the trials of it, made in the Gorgon, Cyclops, and several 

 other vessels, during the last three years, have been most satisfactory 

 and conclusive. 



REVIE^VS. 



Pambour on Locomotive Engines. London : John Weale, 1840. 



(Second Notice.) — (Continued from page 10. J 



In the 11th section it is shewn that on Railways with a wide gauge, 

 like the Great Western, the locomotives have the advantage, at mo- 

 derate velocities, such as 25 miles per hour, of conveying much greater 

 loads, and consuming less fuel per ton per mile, than on railways with 

 a narrow gauge. 



The subject of Adhesion is but superficially treated in the 14th 

 chapter. The adhesion of an engine is not correctly measured by the 

 load it has drawn, but by the greatest load ;/ can possibli/ dram, with- 

 out the driving wheels slipping on the rails, and of this we have no 

 determination; the author has contented himself with shewing, from 

 data furnished by experience, that the adhesive force, when the rails 

 are in good condition, is equal to at least i of the adhering weight, 

 and, when they are greasy and dirty by the effect of wet weather, it 

 is, except in very extraordinary circumstances, at least ^y of the ad- 

 hering weight. 



The limit of the adhesion of an engine might however be deduced 

 from the friction which would result if the engine were dragged along 

 on the rails with the wheels fixed. 



Chapter XV. treats of the effects of the regulator, and in the 16th 

 the effects of the lead of the slide are discussed at considerable 

 length. 



In the 17th chapter the author investigates in a very clear and 

 scientific manner the iuHuence of inclined- planes on the velocity and 

 load of locomotive engines, and deduces therefrom rules which may 

 assist in deciding on the best line to be chosen for a railway between 

 two given points. It is here most satisfactorily proved that the work 

 done in conveying a given load from one point to another is less on a 

 level road than on one consisting of alternate ascents and descents, and 

 that the greater the inclination of the planes, the greater is the amount 

 of work done. 



The ISth chapter, on Curves, completes the theoretical considera- 

 tions of locomotive engines on railways ; but it is evident that the 

 author has not given this subject an equal share of his attenlion, for it 

 is not treated with that perspicuity and just application of science, 

 which characterize most of his investigations. In the 2nd section, 

 when treating of curves of which the resistance is corrected by the 

 conical inclination of the tires of the wheels, he says, page 524, 



"The calculation of these ert'ects evidently depends on two things: 

 the intensity of the centrifugal force produced by the motion of the 

 wagons in the curve, and the intensity of the centripetal force pro- 

 duced at the same time by the inequality of the wheels of the wagons." 



We are assured that, if M. de Pambour had given a little more at- 

 tention to this point, he would have seen that the tendencv of a cone 

 to roll in the circumference of a circle is not due to any force, but 

 simply to the adhesion of its surface to the planes on which it rolls, 

 which prevents one part from slipping while another is rolling, on ac- 

 count of the friction that would ensue. This tendency does not, how- 

 ever, counteract the centrifugal force : it merely corrects the tendency 

 which wheels of equal diameter would have to roll on in a straight 

 line, and which would thus co-operate with the centrifugal force in 

 causing the carriage to run off the rails. If the eftect of the centri- 

 fugal force is counteracted by the conical form of the tires in traversing 

 a curve, without the flanches of the outer wheels coming in contact 

 with the rail, it must be in consequence of the centre of gravity of the 

 carriage being raised by its lateral displacement. 



The Appendix contains a great quantity of useful information con- 

 cerning the expenses of haulage by locomoiive engines on railways, 

 with Extracts from the Report of the Directors of the Liverpool and 

 Manchester Railway, from the opening of the railway, on the lljth 

 September 1S3U, to the 3oth June 1834. 



Notwithstanding the exceptions we have taken to some few por- 

 tions, the chief part of the work will be found highly instructive, and 

 abounding with valuable data; and the practical tables interspersed 

 throughout will be a great assistance in applying the various formula. 



The Science of Vision, or Natural Perspective, containing the True 

 Language of the Eye, Sfc.^c. Second Edition, 24 Plates. By Arthur 

 Parset, M.B.A.A.S. London, 1840. 



Most of our readers, we presume, have heard of that kind of dis- 

 covery which goes by the name of "finding a mare's nest;" and such 

 it appears to us is that discovery in the laws of optics and perspective 



