a and Europe still exists. That is
the Gobi Desert, in Central Asia. This horse is known as Prevalsky's
wild horse, in honour of the Russian traveller who discovered it. Live
specimens are now to be seen in the Zoological Gardens and elsewhere.
It closely resembles the drawings of horses made by the palaeolithic
Cromagnard cave-men. A century ago a wild horse, probably of the same
race as this, inhabited the Kirghiz Steppes, and was known as the
Tarpan: it is now extinct. The more southern Arabian horse is not
known in the wild state, whilst the wild horses of America are
descendants of domesticated European horses which have "run wild." I
do not know of any studies of the movements of the true wild horse,
nor of those of wild asses and zebras, carried out by the aid of
instantaneous photography. It would be interesting to know whether
untaught wild "equines" would fall naturally into the gaits known as
"the amble" and "the rack," or whether the walk, the trot, and the
gallop are their only natural gaits.

The amble, in which the fore and hind leg on the same side are
advanced simultaneously, is a natural gait of the elephant, the
fastest Muybridge could get from that great beast. He made a menagerie
elephant amble at the rate of a mile in seven minutes. The only other
animal known to habitually exhibit "the amble" is the giraffe. It is
often exhibited by the giraffes in the Zoological Gardens in London,
but has not, I believe, been recorded by a series of instantaneous
photographs. When going at full speed over the grass wilds of Central
Africa the giraffe exhibits a gait more like the galloping of deer and
antelopes, and carries the long neck horizontally. No complete study
of the "gaits" of large animals other than the horse has been made,
since menagerie specimens and menagerie conditions are not
satisfactory for the purpose, and, unfortunately, it has not been
possible as yet to take series of photographs of them in their wild
conditions.

The electric spark furnishes a most important means of taking
instantaneous photographs, but the operator must perform in the dark.
An electric spark can be obtained which lasts only the one
two-thousandth of a second, and by its use as the sole illuminating
agent we can get a photograph of a phase of movement lasting only that
excessively short space of time, or, if we please, a succession of
such phases by using a succession of sparks. Thus, a rifle bullet is
readily photogr