Telegraphic Determinations of Longitude. 21 
impact on the ink well. Had there been time for more extensive 
experiment this difficulty might have been overcome. Or if the 
same method had been adopted at both stations, the result would 
have been affected by only the difference between the times of 
movement of the brass spring which would have been minute. 
Lack of time for experiment, and the fact that the observers were 
averse to introducing untested methods into a chain of measure- 
ments most of the links of which were already completed, 
prevented any use being made of this achievement. The meas- 
urement between Greenwich and Lisbon being satisfactorily 
completed. Lieut. Com. Green by order of the Navy Depart- 
ment returned to the United States, and the links between Rio 
and Pernambuco and between the latter place and Para, were 
measured by Lieut. Com. Davis and the writer, completing the 
work of the expedition, after which the party returned to 
Washington. 
The computation of this work, showed the somewhat surprising 
fact that the heretofore accepted position in longitude of Lisbon, 
differed from the true one by about two miles. The longitude of 
Rio Janeiro had always been more or less in doubt, various deter- 
minations had differed by as much as nine miles, but the position 
finally decided upon by the best authorities agreed very closely 
with that obtained by telegraph. 
The next expedition was sent out by the Bureau of Navigation 
to China, Japan and the East Indies, Lieut. Com. Green being 
still in charge. The officers composing the party sailed from San 
Francisco by mail steamer in April, 1881, for Yokohama, where 
they joined the U.S. Steamer Palos. From Hong Kong north to 
Vladivostok in Eastern Siberia the cables were owned by a 
Danish company. From Hong Kong to the south and west they 
were the property of English companies. Beginning at Vladi- 
vostok observations were made at all stations on the Asiatic 
coast except Penang, as far as Madras, India. It was intended to 
try and make some use of the automatic method of receiving 
time signals, on this work, but on arriving in Japan it was found 
that the recording instrument used by the Danish company was 
entirely different from that used by the English lines. It con- 
sisted of a series of electro-magnets acting on a single armature, 
which carried a siphon madé of silver. The signals consisted of 
long and short movements, to one side of the middle line, instead 
of equal deflections on both sides as in the Thompson recorder. 
