236 ttEPOKT— 1872. 



The locomotive eugiue lias for many yeavs past beiug doing very fair duty. Tliis 

 lias arisen, I believe, first, from, the fact tliat since the introduction of coal the 

 furnaces have been to a considerable extent gas-furuaces with a free admission of 

 air through open fire-doors to the surface of the fuel. 



Second, from the fact that the boilers have large absorbing surfaces. From 

 these causes as much as 9 or 10 lbs. of cold water are commonly evaporated per lb. 

 of coal, while the engines working with high steam and considerable expansion 

 make a good use of that steam. 



In Marine Engineering there has within the last ten years been an enormous 

 improvement. The old-fashioned engine working at 20 lbs. steam, and with injec- 

 tion-condensers, is being abandoned for engines generally on the compound-cjdinder 

 principle, working at GO and 70 lbs. steam [highly expansive, and fitted with sur- 

 face-condensers. The result is a reduction of the consumption of fuel in the same 

 vessels on the same voyages, and performed in the same time, of from 40 to 50 per 

 cent, of that which was previously burnt ; but I believe that a large field for im- 

 provement in marine engines still remains, especially iu the firing and in the size 

 of the boiler. 



Among the best instances of what can be done iu the way of economy may be 

 mentioned the rapidly increasing class of portable agricultural engines. 



These engines, like the locomotive, are, from their migratory condition, incapable 

 of being fitted with condensers, and thus must be worked as non-condensing" 

 engines, exhausting their waste steam into the air — a most serious disadvantage. 

 Nevertheless such great advances have been made by the unremitting attention of 

 the extremely skilful mechanical engineers who construct these engines, that at the 

 late Cardiff" Meeting of the Royal Agricultural Society of England one of the 

 engines (the prize engine, that of Messrs. Clayton and Shuttleworth) ran for five 

 hours and one minute with 14 lbs. of coal per horse-power, being therefore a little 

 under 2 ,*u^ lbs. of coal per horse-power per hour; and this was the horse-power 

 of the dynamometer break, and not the mere indicated horse-power by which 

 marine engines and other engines are ordinarily judged. The indicated horse- 

 power is, of course, in excess of that developed upon the break, as the indicated 

 power includes all the engine-friction and break-friction ; and if this latter horse- 

 power be taken as a standard, the best of tlie engines tried by the Koyal Agricul- 

 tural Society this j'ear at Oarditt' will offer favourable comparison with even very 

 good condensing-engines, and will be found to give a duty far beyond that which 

 ten years ago would have been thought obtainable in any but the very best. 



It may be mentioned that the Cornish pumping-engines, which used to be looked 

 upon as the most economic of all engines, are, according to the Juno monthly 

 report, doing onlj' an average duty of 53 Jg- miUious of lbs. lifted 1 foot high for 

 1 cwt. of coals, and that the very best of them is doing only 71f „ millions of lbs., 

 while the break horse-power developed by Messrs. Clayton & Shuttleworth's 

 engine, at Cardiff", gave a duty of 79^-^ millions of lbs. This large duty was due 

 to the great ability in the management of the fire (as has already been hinted at) 

 and to the proper proportion of the boiler in obtaining the steam, and to its thorough 

 cleaning in preserving it in the first instance, and tlien to the efficient utilization 

 of that steam by high expansion in a cylinder steam-jacketed around its circum- 

 ference and at the ends. But at the very same show there competed for the prize 

 an engine which, to the eye of the uninstructed (the ordinary purchaser for example), 

 was as likely an engine as the prize engine ; and yet this engine burnt 10 lbs. of 

 coal per horse-power per hour, or nearly four times that which was burnt by the prize 

 engine ; and, moreover, it must bo remembered that this wasteful engine was one 

 which the maker thought worthy to be sent to trial. How many are there, there- 

 fore, among those which makers do not think worthy to be sent to trial, which 

 must deal as wastefuUy or more wastefully with coal, and are, for the sake of a 

 few pounds in the first cost, bought by ignorant purchasers, who go on committing 

 the sin of wasting coals with such engines until they are worn out, the loss 

 becoming greater with the age of the engine. 



It may be said that hitherto my observations upon consumption in steam- 

 engines have contained quite as much of praise as of blame, and I am glad to say 

 that it has been so ; but it will be foimd that these praises have referred to the 



