Dr Fyfe on the Pyeventlon of Smoke^ 8fc. CI 



nute apertures of the distributor at one time, and at another 

 through the tube in the refrigeratory, being different, from the 

 different conditions under which it was escaping, though the 

 area of the aperture of the stop-cock was in all the trials the 

 same. I had therefore recourse to another method. Instead 

 of taking the steam from the boiler attached to the furnace, 1 

 had another smaller one erected near it, furnished with its 

 own fire, and from which the pipe terminated by the distribu- 

 tor was taken, and conveyed into the large furnace. This 

 small additional boiler was worked under a pressure of 6 lb. ; 

 and to avoid any error from the escape of steam by the safety- 

 valve, the superfluous steam which should have escaped 

 through it was conveyed by a pipe into water, where it was 

 condensed and measured. Deducting the quantity obtained 

 from it from the total quantity given off from the boiler, 

 which was known by measuring the loss sustained by the 

 boiler, the quantity projected through the distributor was as- 

 certained. The average of several trials performed in this 

 way, gave 4 lb. of steam for each 100 lb. evaporated from the 

 boiler connected with the furnace and engine — that is, 4 per 

 cent. Now, supposing this were taken from the boiler with 

 which the evaporative power of the fuel was tried, when sub- 

 ject to the action of the steam distributor, we must deduct it 

 from that discharged from the boiler, and we shall then have 

 the available power in practice, and consequently we shall be 

 able to ascertain whether, by this process, there is an increas- 

 ed amount of evaporation, and if so, what is the saving in 

 fuel. 



It has been already stated, that the average amount of eva- 

 poration with the furnace subject to the influence of the 

 ateam-distributor, was 10.76, presuming the water to be sup- 

 plied to the boiler at 32. Now, deducting 4 per cent, from 

 this, the residue is 10.33. With the same fuel, and witliout 

 the steam -distributor, the evaporation was only 6.17 — thus 

 giving an excess of 4.16, or a little beyond one-half more, by 

 the same quantity of fuel ; consequently, to produce the same 

 amount of evaporation by the common process, and by the 

 use of the steam-distributor, the results shew a saving of fuel 

 amounting to very nearly 40 per cent. 



