1842.J 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



159 



Much has been lately said concerning the preat weight, bad propor- 

 tions, and large consumption of coal, of the Clyde engines ; with what 

 truth, it is not now my intention to inquire, but their makers can bear 

 it well, whfn they recollect, before they became of sufficient impor- 

 tance to be considered as rivals, that the same charge was brought 

 against Boulton and Watt. Mr. Pole, supposing Vulcan to be of 

 " Bromielaw" origin, gives them a very sly hit. He says " Four pairs 

 of 2bO horse power, nude in Scotland, exceeded the assumed weight 

 by 60 tons each pair." If so, it only proves that they (the Scotch) 

 sinned in a greater degree than the Canal Iron Works, in the exact 

 proportion of 2S0 to GO, as 320 is to 40, nothing more. Are we to 

 qualify our own errors, bv exaggerating those of others? No, no, the 

 Gorgon engine is a Thames production : let us try it by its compeers. 

 Here I must accuse Mr. Pole of a quibble. He throws aside all the 

 machinery but the engine, as I observed before; as it regarded space, 

 this is a perfectly fair comparison, but not so as it regards the weight. 

 He has shown the engiie alone to have exceeded its estimate by two 

 tons onlv. True; but engines are scarcely complete without paddle- 

 wheels. To avoid any misunderstanding as to the shafts and other 

 portions being put to debit or credit, let us take them both together, 

 and we have — weight given, 145 tons ; real weight 1G3; a difference 

 of 18 tons. Here lies the quibble: it must be evident, even to the 

 unprofessional reader, that a saving in one portion of a ship's ma- 

 chinery, if counteracted by increased vreight in another, is of small 

 use in result, and that in comparisons of this sort, it is proper only to 

 take the total weight complete. This I do! Vulcan states the Gorgon's 

 weight to be 298| tons, and he has not been directly contradicted. In 

 the table, p. 133, Mr. Pole puts it at 280 tons. Had we not better call 

 upon Vulcan to produce his promised '■official" report upon this sub- 

 ject? Apropos of tiiis very admission, that the Gorgon engine is 

 0'88 of a nominal horse per ton, and that beam engines are about l-O'J 

 ton per horse per hour; the difference here is just 0'12, or less th^n 

 one-eighth, and the pamphlet, see art. 2, promises a saving of 25 per 

 cent., or one-fourth. May not the Messrs. Seaward say, "Save us 

 from our friends V 



This last statement of Mr. Pole is in accordance with my own 

 practice. I have now before me a list of 52 pairs of beam engines, 

 made by an eminent firm, averaging from 300 down to 40 horses col- 

 lectively. The smaller power, say to 2, 60 horse, certainly are not 

 more than "9 of a ton per horse, not being encumbered with coal boxes, 

 a rather formidable affair in very large vessels. The larger powers 

 generally having this additional weight average one ton per horse : in 

 one or two cases this was exceeded, in others not reached, depending 

 on the depth of the vessel, and other data not necessary to be enume- 

 rated. And these weights include engines, paddle-wheels, boiler and 

 apparatus, coal boxes, water, duplicates, and tools, &c. — in fact, 

 complete for service. 



M. Pole states the weight of the Monarch's engines (the Nile's 

 were exactly similar,) at 270 tons. I take this for granted, as I am 

 not able to obtain anv corroboration. Now I have already shown, by 

 reference to Tredgold, that these engines may be increased to 320 

 horses, without increase in space, and by the substitution of a single 

 cylinder G7 inches in diameter for a double or jacketed one 551 inches 

 in diameter, without any material increase in weight. Taking a beam 

 engine at one ton per horse, we have, 320 tons— 270=50 tons surplus, 

 to be expended in strengthening the working parts if necessary, and 

 in increasing the boiler to the required power. I have shown the 

 Medea may be increased to 320 in like manner. Her weight is 240 

 tons, and 320 — 240;=80 tons surplus for purposes above stated. I 

 have no hesitation in saying it is very ample, and that an engine 

 5 ft. 6 in. stroke, as sketched by V^ulcan, could be constructed to 

 weigh no more than 300 tons.* 



The last item is the consumption of fuel. I admire Mr. Pole's wit 

 more than his judgment, in bringing a heavy charge against Vulcan — 

 that of "gratuitous fabrication." He should have been careful of his 

 facts here, as it vitiates a somewhat well-written paper. Vulcan not 

 only speaks of the pamphlet, but also "some of the published state- 

 ments and assumed facts ;" see his second paragraph, certainly a very 

 temperate one. If it can be shown that the Messrs. Seaward have 

 published the fact, thai their engines require 6J lb. only per horse per 

 hour, I apprehend Vulcan's error in having quoted it/;om the pamplet 

 instead of from other papers, will be considered venial. This I 

 will do. 



I have now before me, (and they are sent for your inspection) five 

 publications, hand-bills, call them what you will, the three first extoll- 

 ing "Mr. Samuel Seaward's patent expansion slide valves and salt 

 detector," the fourth a lithograph copy of letters from the commander 



* Would Mr. Alexander Gordon favour us with the weigbt of the Don 

 Juan's engines ?, 



and engineer of the Gorgon, detailing her wonderful and unequalled 

 performances on the north coast of Spain, and the last is a sort of 

 compendium of the foregoing, as well as a species of "olla padrida" 

 of the productions of the Canal Iron Works. It is an extensive afFiir, 

 epistolary in its form, and therefore certainly not intended for private 

 circulation, so that I commit no breach of good manners in bringing it 

 before you. 



In this last production it is worthy of note, that the claim of "saving 

 in weight" is reduced from one-fourth to one-fifth — an improvement 

 in the right direction, most surely. And the 4th article says "a great 

 saving in the consumption of fuel" ; and, further on, (I copy the whole 

 paragraph,) " we guarantee that the consumption of fuel in our marine 

 engines, constructed upon our improved system (that is, the Gorgon 

 engines, for nothing else is hinted at,) shall be under six pounds of 

 good coal per horse per hour, tlie engines working at their full efficient 

 force, with the steam passage open at least four-fifth of the entire 

 stroke of the piston." 



Mr. Pole takes a coraraon-sense view of the question, when ob- 

 serving there is nothing in the "direct system" alone which could 

 produce a saving in coals. But the claim of under st.v pounds is stag- 

 gering in any kind of engine, and being placed alongside other matter 

 of an apocrvphal nature, demands notice. If the saving is not in the 

 engine, it may be in the boiler, or probably in the felt or jacketing. 

 Let us give credit where it is due. 



If there is any irrelevancy in the introduction of this "fuel question," 

 it cannot be asi-ribed to Vulcan, but to the proprietors of the Canal Iron 

 Works, wdio, in vending their Gorgon engine, have claimed for it 

 properties which it does not possess. Is the saving in the boiler? 

 Has it, from its scientific proportions and construction, greater evapo- 

 rating powers than those of other manufacturers? To this I answer, 

 no, so far as my experience and practice will al'iow me to discover. I 

 do not sav thev are copied therefrom, but they have the same arrange- 

 ment of flue as those made by Maudslay some years previously or 

 the Dee, Messenger, Phoenix, Salamander, &c., and I should say were 

 capable of evaporating at atmospheric pressure about 15 cubic feet 

 of water with a cwt. of good coal, that is. about SI lb. of water with 

 a pound of coal. The grate surface is small, being HiS-,) square feet, 

 a little more than half a foot per horse, say 0-52, and I make the total 

 surface (not taking the bottoms of flues) to be about 33SS square feet, 

 or 10-G per horse. 



Vour professional readers will see nothing very new in all this; 

 and if the facts are disputed, I am prepared to spnd you authenticated 

 drawings, not only of the boilers of the Gorgon, but those of the Dee 

 and Messenger, that they and you may draw their own inferences. 

 The clothing onlv remains. I do not know of any experimental know- 

 ledge on this head on which we can rely, to show the ratio of saving 

 by its adoption, but hope at a future time to lay such before you. 

 ' The Messrs. Seaward, in the aforesaid " olla podrida," say "The 

 great saving we are enabled to make in the consumption of fuel we 

 accomplish in part by our new mode of clothing or jacketing the 

 boilers, cylinders, &c." " Our new mode" 1 What is it, and in what 

 does it ditfer from that which has been adopted by other engineers for 

 years before the Seawardian era? Surely all credit on this head is due 

 to "Watt," who was, of all others, the most forward in recommendirg 

 this plan. True, he used sawdust, and found it to answer excellently 

 as a non-conductor. I am old enough to remember that, so far back 

 as 1817, felting the boiler was adopted. Some of your readers 

 probably recollect seeing in the autumn of that year a small vessel 

 called the "Caledonia," which was purchased by the prestnt Mr. 

 Watt, and in which he placed a pair of 14 horse engines, and sub- 

 sequently ascended the Rhine as far ar Coblenz, to show the natives 

 what steam could do. The boiler of this vessel was felted, aye, and 

 carried out to a great extent. The front of it was covered with 

 block tin. I cannot tell the amount of saving in coal, but the comfort 

 of the officers and crew was materially increased. It is unnecessary 

 to follow this subject further, to show the antiquity of the practice of 

 "clothing." I therefore humbly submit that the words "our new- 

 mode" should be expunged from this advertisement, or that the 

 Messrs. Seaward explain unto us on what grounds they put it forth. 



I cannot omit to notice that which follows the foregiiiiig quotation. 

 Speaking of the reduced consumption, they say we are enabled "more 

 particularly to accomplish this bv a most valuable improvement, for 

 which we have letters patent," tliat is, "causing the spent steam from 

 the cylinder, before it enters the condenser, to pass through and give 

 out its heat to the feed water." This I conceive to be as scientific an 

 improvement as could well be devised, and give the Messrs. Seaward 

 great credit for the same. 



But taking all the claimed novelties and improvements detailed in 

 the five publications, together with those in the pamphlet, 1 cannot 

 see any reason to conclude that they would produce so low a cou- 



