[ 57 ] 
fufficient to work the engine, cannot in this be made 
lefs ; and confequently will not admit fuch a laving 
from this model, as from one properly condru&ed 
for the purpofe : a proof of which I made, by try- 
ing fome coals of a weaker kind, which were alfo 
cheaper ; but on trial were not drong enough to 
work the engine, and had therefore been laid by. 
Thefe coals anfwered extremely well ; and, as it was 
a flower-burning coal, I found the confumption, 
whild they laded, was between two and three bufhels 
lefs in every fix hours, which is about the time the 
engine works each day : and I am fatisfied, if the 
perfon, who attends the engine, would take the pro- 
per care, more coals could lfill be faved. For at 
feveral different times, when I had the coals exactly 
meafured, and marked the time, I condantly found, 
that it required half a bufhel in the hour lefs than 
he generally ufed, and the engine threw up as much 
water. 
As this method of blowing air thro’ boiling water, 
in order to increafe the quantity of deam for a fire- 
engine, has, I believe, never before been attempted, 
and produces already a very good effedl, I am in 
hopes it may be dill further improved. 
Vol, 50. 
I 
XI. Ex - 
