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THE FARMER'S MAGAZINE, 



vibration, and that shaftings should never be long enough 

 or thin enough to whip when at work. It is this which 

 causes driving straps to come off. That the foundation 

 of your engine should be solid and sufficient. I think I 

 read that Mr. Salt's great engine, at Saltaire, Bradford, 

 required 1,200 tons of stone for its foundation. That 

 our manufacturers in Mancliester, Leeds, &c., evince 

 their appreciation of the necessity for extreme accuracy 

 in their machinery, by 'the ponderosity of their build- 

 ings. That our tumble-down farmeries are often unfit 

 for the vigorous attachments of mighty steam. That 

 great mistakes are made by bricklayers, engineers, 

 and others, in the erection of engines, flues, and setting 

 boilers. (See Armstrong on Boilers and Williams on 

 Combustion.) That it is very desirable one should know 

 something practically about the matter in which we are 

 so much interested — practically, so as to detect or pre- 

 vent erroneous operations. That your boiler should 

 always be of two or more horse-power than your engine, 

 and that both should be well master of their work. That 

 the absence of glass water-gauges and the mere use of 

 steam-cocks, too common in many of our manufac- 

 tories, is a dangerous and costly neglect, often resulting 

 in accident, or in the burning of the boiler plates, and 

 interruption of the works. That all high, pressure 

 engines should have a Bourdon steam-gauge, and also a 

 mercurial steam-gauge. 1 am a believer in Craddock's 

 theory of explosions, and also in Dr. Allban's proposi- 

 tion, that there is much less ebullition with high-pressure 

 than with low-pressure steam, the steam bubbles being 

 infinitely smaller by greater coropression. That we owe 

 a debt of gratitude to Mr. Wye Williams, who has taught 

 us to prevent smoke and economize fuel, and who has 

 also enlightened us on the circulation of water in steam- 

 boilers. That the steam-chamber, or steam portion of 

 the boiler, should be enveloped in a heat greater than 

 its own temperature, but not sufficient to make the 

 boiler-plates of too high a temperature. That excessive 

 heat in the ash-pit, red-hot fire-doors and furnace- 

 plates, and over-heated fire-bars, indicate either the 

 absence of a sufficient supply of air to the upper portion 

 of the fuel, or inadequate draught or flue room. That 

 multitubular boilers have their joints loosened by too 

 intense heat passing inside the tubes. That such boilers, 

 when attached to, and above, a Cornish boiler (as in Mr. 

 Hall's case), do not suffer injury, but utilize the heat 

 which passes through them. The advantages of high 

 pressure, great expansion, and rapid movement of the 

 slide, are fully availed of in the locomotive ; there the 

 pressure is often 140 lbs. per inch, the steam cut off at 

 l-24th of the stroke, and the stroke or slide movements 

 very quick. The effect of all this is admirably explained 

 by Dr. AUban. The rapid and almost continued exit 

 of the steam c mses a vacuum in the exhaust-pipe, and 

 thus relieves the piston of a large portion of the pres- 

 sure of the atmosphere, whilst the gain from expansion 

 at 140 lbs. pressure per inch is very large, as shown in 

 Craddock's tables. It must be borne in mind that com- 

 pression of steam costs us nothing more than the 

 expense of a somewhat stouter boiler. It costs no more 

 fuel to produce steam at high pressure than in an ordi- 



nary open copper {vide Armstrong). When travelling 

 on the Great Northern by express, the engine-driver 

 told me he worked his engine at 140 lbs. pressure per 

 inch. The most economical management I know of 

 with high-pressure steam, not condensed, is that prac- 

 tised by Mr. Collinson Hall, of Prince's Gate, Romford. 

 He works three pairs of mill-stones at a cost of five 

 shillings per day for coals. This may be considered 

 equal to eighteen-horse power, or thirty-six horses per 

 diem. His pressure is 120 lbs. per inch, worked ex- 

 pansively. The peculiarity is having a multitubular 

 boiler fixed above, and attached to, a Cornish boiler, 

 the heat passing through and then around both boilers, 

 including also the steam space. I very much admire 

 the economy and safety of the arrangement, the Cornish 

 boiler being always full of water. In fact, Mr. Hall's 

 success is partly owing to his superheating the steam in 

 his upper boiler. No doubt you are aware that this 

 principle is being acted upon extensively by the Penin- 

 sular and Oriental Steam Navigation Company, who 

 hope to save some 30 per cent, on the £'700,000 which 

 they pay annually for coals ; the subject is well worthy 

 the attention of agriculturists. Some years ago the 

 American government caused a commissioner to report 

 on the suggestions of Mr. Frost, an Englishman, on 

 super-heated steam, and confirmed his views of its 

 economy. We all know that a very slight degree of cold 

 diminishes the expansion and pressure of steam, and it 

 is easy to comprehend that the opposite of this increases 

 its power ; practically I have acted on this principle for 

 some time, by allowing my last flue to encircle the steam 

 space of my boiler : a heat of 650 degrees has no inju- 

 rious effect in this respect. No doubt it was this consi- 

 deration that caused Mr. Hornsby to place his cylinder 

 in his boiler; and I think Messrs. Tuxford place 

 theirs in the smoke-box. A fearful loss of power 

 is often occasioned by exposing a long supply steam- 

 pipe to atmospheric influence. Cornish boilers are 

 dangerous for high-pressure, if the upper surface 

 of the internal flue is uncovered or only slightly 

 covered by water. The danger is at starting, when the 

 water rises over the red-hot portion of the flue ; it is 

 like plunging a red-hot mass of iron into water. Many 

 a new good Cornish boiler has been ruined by the stoker 

 raking out a red-hot fire, and thus suddenly exposing 

 the boiler to a full blast of cold air from the open door. 

 The sudden and unequal contraction starts the rivets, 

 and makes the boiler leak. I have been told that the 

 admission of cold air through the furnace-doors, on 

 Williams's plan, is apt to affect Cornish boilers. Pro- 

 bably a deflecting plate would prevent this. All sudden 

 and violent changes of temperature are injurious to 

 boilers. 



Mr. J. A. Williams (Baydon, Hungerford) wished 

 to offer a few remarks on this subject, it being one in 

 which he had taken peculiar interest. * It was seven 

 years ago since he first commenced applying his mind to 

 the question of steam-cultivation, and he was now con- 

 vinced that nothing scarcely had a more direct bearing on 

 the improvement of agriculture. Four years ago he in- 

 troduced before the members of that club the question of 



