632 Report on the Trials of Combined Stacking-Machines 
or four minutes, with an effort that could not be sustained 
throughout a day's work. The slowest work was done by 
Wallis and Steevens's machine ; but even in this case we find 
that, dividing the figures in column 7 by the four minutes, the 
power required slightly exceeds the 33,000 foot-pounds that 
Watt estimated a horse could perform per minute. While in the 
case of Coultas's machine 47,300 foot-pounds of work was done 
per minute, nearly half as much again as the theoretical horse- 
power, although that power is itself in excess of the average 
performance of farm horses. Columns 8, 9, 10, and 11 need no 
comment. 
The ratios " given in column 12 show that the greater 
part of the force expended by the horse serves simply to 
move the machine, and from 6 to 7 parts out of 10 are thus 
expended. The average efficiency of the three machines with 
independent horse-works is '35, while that of the two self-con- 
tained machines, last on the list, is '34. It would not, however, 
be safe to conclude at once that there is no mechanical advantage 
in placing the horse-gear immediately below the trough. 
Although when the horse-gear and elevator are thus tested 
as one whole machine, the advantage appears slightly to incline 
towards those that have horse-gears separate, we have yet to 
see whether this may not be solely due to superior mechanical 
construction in the ladder-chains and chain-wheels. 
An examination of columns 13 to 18 Avill show that this is 
really the case. In this fifth trial the machines were tested 
apart from their horse-works ; and in column 18 we find the 
average efficiency of the three machines first on the list is '53, 
while that of the other two machines is only "48. From this we 
may conclude that, so far as the horse-works alone are concerned, 
the self-contained machines have slightly the advantage, but that 
this is more than counterbalanced by the greater advantage 
which the other three machines possess in the construction of 
the parts of the elevator itself. Column 19 gives the average 
of columns 12 and 18, and determines the points of merit in 
column 21. 
A sixth and final trial was made before points were awarded 
in column 22. 
In threshing out corn in a well-filled rickyard, it is often of 
great impoitance that the elevator should be capable of removing 
straw at any angle from the threshing machine, so that the 
straw-rick may be built wherever there is room for it. This 
sixth trial was made so late in the week that we could not 
obtain from the show-yard the loan of the engine and threshing 
machine first selected. Eut at a very short notice we obtained 
an engine from Messrs. Aveling and Porter (lent with that 
