a geological and topographical cross section along the 73d meridian
through a practically unknown region, and across one of the highest
passes in the Andes (17,633 ft.), had delayed the surveying party to
such an extent as to make it impossible for them to reach Coropuna
before the first of November. On account of the approach of the cloudy
season it did not seem wise to wait for their coöperation. Accordingly,
I secured in Arequipa the services of Mr. Casimir Watkins, an English
naturalist, and of Mr. F. Hinckley, of the Harvard Observatory. It
was proposed that Mr. Hinckley, who had twice ascended El Misti
(19,120 ft.), should accompany us to the top, while Mr. Watkins,
who had only recently recovered from a severe illness, should take
charge of the Base Camp.

The prefect of Arequipa obligingly offered us a military escort in
the person of Corporal Gamarra, a full-blooded Indian of rather more
than average height and considerably more than average courage, who
knew the country. As a member of the mounted gendarmerie, Gamarra had
been stationed at the provincial capital of Cotahuasi a few months
previously. One day a mob of drunken, riotous revolutionists stormed
the government buildings while he was on sentry duty. Gamarra stood
his ground and, when they attempted to force their way past him, shot
the leader of the crowd. The mob scattered. A grateful prefect made
him a corporal and, realizing that his life was no longer safe in that
particular vicinity, transferred him to Arequipa. Like nearly all of
his race, however, he fell an easy prey to alcohol. There is no doubt
that the chief of the mounted police in Arequipa, when ordered by the
prefect to furnish us an escort for our journey across the desert,
was glad enough to assign Gamarra to us. His courage could not be
called in question even though his habits might lead him to become
troublesome. It happened that Gamarra did not know we were planning