LX. J. F. FURNISS. 



In the stroke of this engine the steam was carried for 

 about 2|- tenths. Mr. Furniss also explained the provision 

 made for "cushioning" in this engine, and stated that the 

 lack of economy in the machine was due to the slow speed 

 of the piston. The maker's specification had stipulated 

 that the piston speed should be as low as 4 strokes per 

 minute and not higher than 10 strokes per minute, which 

 latter speed would only amount to 60 feet per minute. In 

 the trial the speed had to be increased largely in order to 

 obtain the contract duty. The steam condensation at the 

 trial was 13/° and a duty of 69 million pounds was shown. 

 The contract duty was 60, and since the trial the engine 

 had produced a duty as high as 70 millions. One feature 

 about this engine was that, while its economy was satis- 

 factory, it was about as true a weighing machine as it was 

 possible to construct, that was in connection with its 

 measuring of its load; true the head load was always con- 

 stant, but the suction load was a varying one. 



The slide showing the Spottiswoode sectional elevation 

 was the wonderful engine in Melbourne that had brought 

 steam consumption down to 13*65 pounds per pump HP. 

 Notwithstanding this, the mechanical efficiency was not 

 so great as might be expected. The mechanical efficiency, 

 as he took it was the indicated HP. as calculated from the 

 card set against the actual work done by the engine. Mr. 

 Selfe had been in doubt as to how this was arrived at. It 

 was a simple calculation, and the only trouble about truly 

 arriving at it was that you had to be positive that the 

 cubical contents of the pump were a true measure of the 

 work done. This could only be positively arrived at by 

 having a measured tank for the pump to fill. The oppor- 

 tunity of verifying these tests by actual trial was taken 

 by the officers of the Water and Sewerage Board when 

 measured reservoirs happened to be empty for cleaning 



