22 National Geographic Mugazime. 
An attempt was made to convert this instrument into a relay, by 
causing the siphon to make and break a circuit, but it was not 
successful. The movements of the siphon were not regular 
enough, and the contact was not firm. Consequently the mirror 
method of exchanging signals was still adhered to. 
The longitude of the position occupied in Vladivostok, had 
been determined telegraphically from Pulkova, by the Russians, 
using the land lines across Siberia. The English had also deter- 
mined the position at Madras, using the cables through the Medi- 
terranean and Red Seas. The work of the United States 
Expedition joimed these two positions, completing a chain of 
measurements extending over many thousand miles, made by 
observers of different nationalities in various climates. It was to 
be expected that considerable discrepancy would be found in the 
final result, but taking the longitude of Vladivostok as brought 
from Madras, and comparing it with that determined by the 
Russians, the difference was only 0%.39. Taking everything into 
consideration, this result was gratifyingly close. Upon the con- 
clusion of this series of determinations, the connection of Lieut. 
Commander Green with the work was severed, he Sees his 
promotion to the rank of Commander. 
The next work was under the chargé of Lieut. Com. Davis, and 
consisted in the determination in 1883-84, of positions in Mexico, 
Central America and the west coast of South America. Cables 
had just been completed, extending from Galveston, Texas, to 
Vera Cruz, thence across Mexico to the Pacific and down that 
coast to Lima, Peru, where connection was made with another 
system extending to Valparaiso. Galveston was a point deter- 
mined by the Coast Survey, and the measurement thence to Vera 
Cruz was the first one made. It was completed in May ’83, and 
in the Autumn of the same year the party proceeded to the South 
American coast, and stations were established and observations 
made at various points from Valparaiso to Panama, and at one 
point, La Libertad, in Central America. It was at first the inten- 
tion to extend the series across the Isthmus of Tehuantepec and 
connect with Vera Cruz, but Jack of time prevented this, and as 
the station at Panama determined nearly ten years before, afforded 
a gonvenient starting point, the idea was abandoned. From Val- 
paraiso, a measurement was made with the codperation of Dr. 
Gould to his observatory at Cordova, using the line across the 
Andes, and exchanging signals automatically. These measure- 
