FIRE HORSES. 231 
in going around a corner. By this device the neces- 
sity of a wide turn is avoided, and the driver is 
able to “cut” the corners as closely as if he had an 
ordinary length of vehicle behind him. 
Sometimes a tough spiral spring, made of steel, is 
inserted in the trace of a fire horse’s harness, near the 
whiffletree, the object being to lessen the strain at 
starting. This ingenious device enables the horses 
to exert their strength against a yielding connection 
instead of a dead weight, —a certain momentum be- 
ing acquired before the whole load moves. On the 
same principle, the couplings which unite a train of 
loaded cars must be somewhat loose, in order that the 
locomotive may start the train. Motion is then com- 
municated from the first car to the second, and so on, 
as the spectator readily perceives ; whereas, if all the 
couplings were tense, the whole train would have to 
start at once. The spring just described might be 
used with all draft horses. 
In the city proper, where most of the runs are 
short, the whole distance is usually covered at a gal- 
lop, unless some hill or obstruction intervenes; and 
this performance tries the animal of whom it is re- 
quired through and through, so that if there be a 
weak spot in him it is soon discovered. In the first 
place, he must be big and heavy. Boston fire horses 
vary from 1,200 to 1,600 pounds, —very few indeed 
quite reaching the maximum, and most of them 
weighing about 1,400 pounds, — rather less than more. 
But the fire horse must also be active, as well as big 
and strong; he must have good feet, good wind, and, 
finally, to execute his ordinary task, he must be in 
hard condition. When the horses are first bought, 
