.S/A- //Y/./././.I/ .v//-:.J//-:.v\, /-:/i'..v 95 



by means of a steam jacket and lagging against loss by condensa- 

 tion within the working cylinder, and that more care is generally 

 bestowed upon the boiler and the parts of the engine, to ensure 

 their proper working condition. 



A striking illustration of what can be accomplished in a short 

 space of time was brought to light by the Institute of Mechanical 

 Engineers, over which I have at present the honour to preside. 

 In holding their annual general meeting in Liverpool in 1863, 

 they instituted a careful inquiry into the consumption of coal by 

 the best engines in the Atlantic Steam Service, and the result 

 showed that it fell in no case below 4| Ibs. per indicated horse- 

 power per hour. Last year they again assembled with the same 

 object in view in Liverpool, and Mr. Bramwell produced a table 

 showing that the average consumption by 17 good examples of 

 compound expansive engines did not exceed 2j Ibs. per indicated 

 horse-power per hour. Mr. E. A. Cowper has proved a consump- 

 tion as low as 1| Ibs. per indicated horse-power per hour in a 

 compound marine engine, constructed by him with an intermediate 

 superheating vessel. Nor are we likely to stop long at this point 

 of comparative perfection, for in the early portion of my address I 

 have endeavoured to prove that theoretical perfection would only 

 be attained if an indicated horse-power were produced with ~ lb. 

 of pure carbon, or say lb. of ordinary steam coal per hour. 



Here then we have two distinct margins to work upon, the one 

 up to the limit of say 2 Ibs. of coal per horse-power per hour, 

 which has been practically reached in some and may be reached in 

 most cases, and the other up to the theoretical limit of j lb. per 

 horse-power per hour which can never be absolutely reached, but 

 which inventive power may and will enable us to approach ! 



Domestic Consumption. The wastefulness of the domestic 

 hearth and kitchen fire is self-evident. Here only the heat 

 radiated from the fire itself is utilised, and the combustion is 

 generally extremely imperfect, because the iron back and excessive 

 supply of cold air, check combustion before it is half completed 

 "We know that we can heat a room much more economically by 

 means of a German stove, but to this it may be very properly 

 objected that it is cheerless, because we do not see the fire or feel 

 its drying effect upon our damp clothing ; moreover, it does not 

 provide in a sufficient degree for ventilation, and makes the room 



