m which was produced by the mingling of these fountains were
pure, limpid, and delicious, and were possessed of remarkable
medicinal properties, being efficacious for the cure of various
diseases. Darius was so much pleased with this river, that his army
halted to refresh themselves with its waters, and he caused one of his
monuments to be erected on the spot, the inscription of which
contained not only the usual memorials of the march, but also a
tribute to the salubrity of the waters of this magical stream.

At one point in the course of the march through Thrace, Darius
conceived the idea of varying the construction of his line of
monuments by building a cairn. A cairn is a heap of stones, such as is
reared in the mountains of Scotland and of Switzerland by the
voluntary additions of every passer by, to commemorate a spot marked
as the scene of some accident or disaster. As each guide finishes the
story of the incident in the hearing of the party which he conducts,
each tourist who has listened to it adds his stone to the heap, until
the rude structure attains sometimes to a very considerable size.
Darius, fixing upon a suitable spot near one of his encampments,
commanded every soldier in the army to bring a stone and place it on
the pile. A vast mound rose rapidly from these contributions, which,
when completed, not only commemorated the march of the army, but
denoted, also, by the immense number of the stones entering into the
composition of the pile, the countless multitude of soldiers that
formed the expedition.

There was a story told to Darius, as he was traversing these regions,
of a certain king, reigning over some one of the nations that occupied
them, who wished to make an enumeration of the inhabitants of his
realm. The mode which he adopted was to require every man in his
dominions to send him an arrow head. When all the arrow heads were in,
the vast collection was counted by the official arithmeticians, and
the total of the population was thus attained. The arrow heads were
then laid together in a sort of monumental pile. It was, perhaps, this
primitive mode of census-taking which suggested to Darius the idea of
his cairn.

There was a tribe of barbarians through whose dominions Darius passed
on his way from the Bosporus to the Danube, that observed a custom in
their religious worship, which, though in itself of a shocking
character, suggests reflections of salutary influence for our own
minds. There