Report on the Trials of Implements at Oxford. 461 
stated to the jM'aise of this exhibitor that he provided a feed-water heater ; 
which, however, he could not use during the trial for the reasons already 
stated. 
Section II. — Horse Gears. 
There is still, even in England, a very considerable use of Horse Gears, 
farmers alleging that there are times when horses, which must of necessity 
be kept on the farm, are not fully employed, and when their power can be 
exerted in propelling machinery by the agency of horse gear, without any 
appreciable extra cost over and above that which would be incurred if they 
were merely engaged in the profitless occupation of "eating their heads 
off;" and in foreign countries, where steam-engines have not yet been so 
commonly adopted as they have been in England, animal power is generally 
relied on. That the trade in these gears is very large, may also be gathered 
from the fact that no fewer than 70 were exhibited by 41 exhibitors, and a 
large proportion of these gears were entered for trial. 
The Engineer-Judges found themselves directed to determine upon the 
merits of these animal power machines, and to try them (but how they were 
to try them did not appear). This direction for trial seems sufSciently 
simple in the case of steam-engines, for the well-known and time-honoured 
appliances for that purpose are, as has already been explained in the Report 
on that subject, provided by the Society, but no means existed for the trials 
of the Horse Gears, nor could the Judges learn that there had ever been any 
efficient trial of these machines. 
Any person conversant with mechanics will know that in an apparatus the 
especial object of which is to convert a slow motion of some two or three 
revolutions per minute into a motion of from 100 to 1-50 revolutions per minute, 
it would be useless to endeavour to test the merits of such a machine by work- 
ing from the quick-going shaft back to the slow-going one, and they would also 
know that any attempt to try the machine by less than the working load 
which would come upon it in practice would be likely to give fallacious indi- 
cations ; and he will thus understand why it became necessary to devise a 
means by which the gears might be worked for trial under similar circum- 
stances to those in which they woidd be used in practice. 
Fortunately for the trial, traction engines exist which can be employed 
in lieu of horses as a motive power for horse gears. 
Taking advantage of this fact, an apparatus was arranged which consisted of 
a temporary wooden drum 8 feet in diameter. This drum was fixed to the 
poles of the two horse gears, and round about it was coiled a rope 100 
yards in length, the end of this rope being attached to a dynamometer 
spring link, which was in its turn attached to the draught-hook of one of 
Aveling and Porter's traction engines. The description will be better under- 
stood by reference to the accompanying illustration (see next page) from a 
photograph by J. Guggenheim. There was thus provided a means by which 
the horse gear could be caused to rotate at a proper pace as the engine slowly 
drew away uncoiling the rope from the drum, and also by the link there was 
afforded a means of ascertaining what tractive force was being exerted to 
draw out this rope. This tractive force multiplied into the distance passed 
over by the engine represented the power consumed in working the horse 
gear. 
For the purpose of finding out what useful effect the horse gear delivered, 
nothing more was needed than to cause it to work one of the dynamometer 
breaks which have already been described in the Eeport upon the engine 
trials. 
By these means that percentage of the power employed, which was delivered as 
2 I 2 
