SHIFTING OF THE EARTH'S AXIS 423 



of the southern end of the Caspian Sea, six miles northwest of the 

 city of Tschardjui and two miles from the left bank of the Amu Daria, 

 or Eiver Oxus. The observatory is located on an oasis in a sand-waste 

 traversed by many canals. There is a greater range in the annual 

 temperature at this station than at any of the others. Tschardjui is 

 affected by very few earthquakes. The observations at this station are 

 made by a single observer, several having taken part thus far, all of 

 them officers of the Eussian army. 



The Italian station is very picturesquely located on an old tower, 

 San Vittorio, close to the city of Carloforte, on the island of San 

 Pietro, which lies west of the southern end of the island of Sardinia. 

 The tower is located on a peninsula on the east side of the island, so 

 that the meridian of the observatory lies almost entirely over the 

 Mediterranean Sea, and anomalies in refraction would seem to be 

 absolutely excluded. The island is free from mountains, the highest 

 point being some 650 feet above sea-level. Carloforte has 8,000 in- 

 habitants and can be reached from Cagliari, the chief city of Sardinia, 

 in eight hours. The meteorological conditions at Carloforte are very 

 favorable. The annual variation of temperature is less than at any 

 other station and over 70 per cent, of the nights are clear, a condition 

 which prevails, I believe, in no other section of the world than that 

 surrounding the Mediterranean Sea. The island is free from earth- 

 quakes, there having been only four in nearly four hundred years of 

 any considerable intensity, and none of these destructive. The ob- 

 servations at this station are made by two observers, who alternate with 

 the nights. Several changes in the staff have taken place thus far, but 

 all its members have been Italian astronomers. 



The station in the eastern part of the United States is located half 

 a mile south of the village of Gaithersburg, Maryland, twenty-one miles 

 northwest of the city of Washington. The surrounding country is 

 hilly, the observatory has an altitude of 540 feet above sea level and the 

 meteorological conditions are fairly favorable. Mr. Edwin Smith, of 

 the Coast and Geodetic Survey, made the observations at this station 

 during the first year; Dr. Herman S. Davis during the succeeding 

 five years. The work is now in charge of Dr. Frank E. Eoss. 



After the parallel of 39° 8' had been selected for the location of 

 the latitude observatories it was found that this parallel passed through 

 the grounds of the Observatory of the University of Cincinnati, and 

 Professor J. G. Porter, director of the observatory, volunteered to 

 carry on observations if he were provided with an instrument. The 

 observatory is located on a hill, five miles northeast* of the city, and 

 one mile east of the Ohio Eiver. The altitude of the observatory is 

 800 feet above sea-level and the meteorological conditions are fairly 

 favorable. Thus far all of the observations, except a few during the 

 summer months, have been made by Professor Porter. 



