It taught him how small his chances were of capturing such game, so long as he could only follow it _afoot_.
The hunter on foot stands but a poor chance with the elephant.

Stalking in upon one is easy enough, and perhaps obtaining a single shot; but when the animal trots off through the thick jungle, it is tedious work following him.

He may go miles before halting, and even if the hunter should overtake him, it may be only to deliver a second shot, and see the game once more disappear into the bushes--perhaps to be spoored no farther.
Now the mounted hunter has this advantage.

His horse _can overtake_ the elephant; and it is a peculiarity of this animal, that the moment he finds that his enemy, whatever it be, _can_ do that thing, he disdains to run any farther, but at once stands to bay; and the hunter may then deliver as many shots as he pleases.
Herein lies the great advantage of the hunter on horseback.

Another advantage is the security the horse affords, enabling his rider to avoid the charges of the angry elephant.
No wonder Von Bloom sighed for a horse.