4 RESEARCH IN CHINA. 
carried a route survey as far as Si-ta-yang. Recently arrived from India, 
he was unable to stand the rigors of January in North China, and becoming 
ill was sent back to Tientsin. The geologists, Messrs. Willis and Black- 
welder, from time to time executed route surveys, usually with compass 
and pacing, occasionally with plane-table and stadia. These have been 
adjusted to the topographic control and incorporated in the details of 
the maps. The topographer is alone responsible for the astronomical 
observations, the results of triangulation, and the delineation of features 
by contours. 
I was dependent entirely upon native assistants, who in the beginning 
were ignorant of the services required, and with whom I could communicate 
only through their slight knowledge of English. ‘wo of our Chinese 
servants aided more or less in the work and one of them, Siau-ir-ko, a man 
of unusual strength and energy, generally accompanied me. He quickly 
grasped the routine of setting up the instruments on stations and the 
manipulation of the stadia rod. Though a native of the plains, he became 
a fearless and skilful mountain climber. He was untiring and loyal and 
his services were of high value. 
The instruments employed in the work were a theodolite, a sextant 
with artificial horizon, telescopic alidades, plane-tables, box and prismatic 
compasses, and aneroid barometers. The theodolite, which was loaned by 
the British Intelligence Bureau through the interest of Colonel Wingate, 
was of English make. The objective was one inch in diameter, with a 
focal length of 8 inches. The horizontal and vertical arcs were 5 inches 
and 44 inches in diameter, respectively, and each vernier was graduated 
to the nearest 15 seconds. ‘The vertical arc and its level were attached 
to the axis of the telescope, which, when not in use, was lifted from the 
Ys and packed separately from the base. The Ys were of sufficient length 
to permit transiting the telescope without lifting it from them. The 
sextant did not differ materially from those in general use, except that 
it was much heavier in construction. Its vernier read to the nearest 10 
seconds. The alidades, plane-tables, and tripods were loaned by the 
United States Geological Survey, and were of the types regularly in use 
in operations in the United States. They are fully described in the Manual 
of Topographic Surveying by H. M. Wilson.* The stadia rod was made 
up of painted aluminum plates, each one foot in length, which were 
carried separately and attached to a board or pole when needed. 
The methods of the survey were adapted to the character of the country, 
the conditions of atmosphere, and the rate of progress required by the 
* Chapter VII, Article 56. 
