Two MARINE INSTALLATIONS OF PRODUCER GAS 225 



Coal burned (allowing 74 pounds to fill pro- 

 ducer at end of trip) 1,408 lbs. 



Coal per indicated horse-power i .13 lbs. 



Weightof engine complete, approximately. . . 9,500 lbs. 

 Weight of producer 6,000 lbs. 



Total 15,500 lbs. 



Weight per B. H. P. (75 B. H. P. commercial 



rating) 205 lbs. 



Economy of space is important, the length of 



engine and producer room being but . ... 13 ft. 3 in. 



No particular economy or horse-power tests were made on the Superior. 

 She is used as a fish-runner out of Bayfield, Wisconsin, collecting fish among 

 the Apostle Islands. This service is probably the most severe that a pro- 

 ducer plant can be subjected to as it is constantly stopping and starting. 

 Some ten to fifteen wharves are made in the course of the day with stops 

 of from five to thirty minutes. 



DISCUSSION. 



Mr. H. a. Everett, Member (Communicated) : — I should like to say a word 

 with reference to the curve of indicated horse-power on revolutions per minute 

 shown on the last plate of Mr. Page's paper. This curve is radically different from 

 any similar curve previously published and is, I think, open to serious question. 

 The commonly accepted theory of the propeller (Froude's) for screw propelled 

 ships gives us the fact that the indicated horse-power is proportional to the cube 

 of the revolution per minute, at least approximately, but the curve here shown 

 has the indicated horse-power proportional to the first power of the revolution per 

 minute, a straight line, in fact; and in view of its peculiarity it would seem desir- 

 able for Mr. Page to indicate the experimental points used in plotting the curve. 



Mr. Page (Communicated) : — I have noted Mr. Everett's comments on the 

 horse-power curve shown on Plate 75. His point is undoubtedly well taken. 



A very considerable number of indicator cards were taken, ranging from 210 

 to 300 revolutions per minute. These when plotted averaged up about as shown 

 on plate. Had cards been taken at lower speeds, the general character of the 

 horse-power curve would undoubtedly have shown up as suggested by Mr. Everett. 



