524 



REPOKT 1879. 



10. Observations were taken of the quantity of air passing into the fireplaces, 

 ■which was recorded by an anemometer. 



11. A record was taken as to the actual weight of Coal, dirt, men and water 

 lifted during the continuation of the experiments. 



12. Diagrams (continuous and single) of the cylinders were taken to show the 

 power expended by the engine in raising Coal and water, and when working with 

 empty tubs. 



The chief data as to the experiments are shown in the accompanying 

 statement. 



Abstract of Experiment*. 

 Duration of experiments 

 Coal used 



Ash and clinker produced 

 Water used 



„ „ per lb. of coal 

 Coal drawn 

 Dirt, water, and men 

 Slack lifted by hoist . 

 Total number of draws 

 Average temperature of feed water 



„ „ at damper 



184-5 hrs. 

 29,344 lbs. 



1,737 „ 



76,080 „ 



2'59 



2,251,072 lbs. 



2,668,995 „ 



805, 728 „ 



3,128 „ 



180° „ 



800° „ 



Although the experiments extended in all 184-5 hours, the time occupied by 

 the engine in actual work did not exceed nine hours per day. 



The most interesting results of the experiments may be briefly enumerated as- 

 follows : — 



1. Only 20 per cent, of the fuel used was utilised in the evaporation of water, 

 and no less than 37 per cent, of the heat in such fuel is not accounted for. 



2. Only 3 per cent, of the heat expended in evaporating water is utilised in 

 actual useful work done, and thus of the 15 per cent, which was available for 

 work, £tk (3 per cent.) was actually utilised in the cylinder of the engine. 



3. Instead of 11-1 per cent, of heat employed being utilised, as found by indi- 

 cations from an engine of the best type, the utilised heat in the case referred to 

 only amounts to -69 per cent., or T \th of the result obtained in a first-class engine. 



4. The fact that at least 41 per cent, of the total heat is found to have gone up 

 the chimney, when if the coal had been properly consumed, probably not more 

 than 20 per cent, would have been lost in this direction, illustrates the manner in 

 which a great loss may take place when the ingress of air and the mode of fixing 

 the boiler are not properly looked to. 



5. The power exerted in moving the dead useless load upon the engine re- 

 presents 40 per cent, of the total power, as shown by the indicator diagrams. 



It is to be feared that the results of the working of the engine and boilers in 

 question are typical of the conditions under which a large number of engines in 

 this country are worked; and although the remarkable waste shown by the 

 series of experiments recorded cannot but suggest the idea of badly arranged plant, 

 the author ventures to submit that the tests are of value in pointing out the 

 importance of such tests being made more frequently, and the extra worth they 

 have when they extend over so long a period (including working and idle time) 

 as 184-5 hours. Had an experiment been made only for a few hours, there is no 

 doubt that a much better result would have been obtained, and this has been proved 

 by the author in this case. In making experiments of this description, the very 

 best form of instruments is required ; and if such instruments were in the 

 hands of a careful observer for carrying out a series of tests on a more com- 

 plete scale than the anthor has been able to arrange, he would not fail to 

 render good service to engineering knowledge. 



The author, however, thinks it right to add that in another arrangement of 

 plant at the Nunnery Colliery, which is to be visited by the members on the 

 29th instant, very different results from those recorded have been arrived at 

 in tests made with well-arranged boilers, and he ventures, by way of comparison, 

 to refer to these tests. 



