190 
ME. MACQUOEN EAKETIVE ON THE THEEM0-DTNA3nC THEOEY 
Example I.— -Paddle-steamer of 820 tons displacement, with a pair of double-cylinder 
engines of 7 44 indicated horse-power. 
Bottom of cylinders. Top of cylinders. 
Data : — lb. per square inch. 
_p,-f-144 33-7 34-3 
^3-^144 ^;0 ^ 
T 4 ^ 6 ^ 
46 1*2= about 104 °Fahe. 
KeSULTS by exact formula : — Bottom of cylinders. Top of cylinders. 
v^=.rv^ 50’375 74-4 
7-367 4-867 
W 109552 117338 
w 
~=w~144 15-1 10-95 
Mean 13-03 
Obsekved mean effective pressure, lb. on the inch . . . 13-10 
Difference . . . — 0-07 
lb 
144v^ 
144 
Mean 
906989 92567S 
125 86-4 
. . . 105-7 
0-121 0-127 
_ ^ ^ . mean w n o o 
Mean efficiency 
Example I., calculated by approximate formula. 
Data : — ff • 
Mean . . . j?i-“144 34 
Mean . . . jp3-~144 4 
Mean ... - 0-2 
?■ 
KeSULTS : ll*- P«^r inch. 
w-j-144. Calculated 13-17 
Observed 13-10 
Difference .... 0-07 
/i^l44 105-4 
E 0-125 
