a 
‘d 
O. H. Landreth—Transit of Venus. 429) 
prevented by clouds which continued to obscure the sun almost 
without interruption until 641" 12", after which the sky re- 
mained clear during the day. 
Instrumental Constants and Circumstances. 
Adopted latitude of equatorial dome = +36° 87 5877-25. 
Adopted longitude of equatorial dome = +0* 39™ 0-68" from Washington. 
perture of equatorial 
Focal length of equatorial = . 
Magnifying power used = 210 diameters, 
Value of one revolution filar micrometer screw I — : 
IE 211297, 
Diameter of cross-wires in filar micrometer = less than 0/34 (15 measurements). 
Aperture of transit circle used for time determination = 3-92 inches. 
Focal length of transit circle used for time determination = 54°00 inches. 
The adopted latitude and longitude depend on the position 
of the astronomical station of the U. S. Coast and Geodetic 
Ing students, with an engineer’s transit and a suspended fine 
steel wire corrected for deflection, temperature and inclination. 
The adopted value of the astronomical position of the coast. 
survey station as furnished me by the office is: 
Latitude = +36° 10’ 1°37. 
Longitude = +0" 38™ 55°897° from Washington, 
clock rate and correction to the assumed clock error. 
lue of one revolution of the micrometer screw was 
the “double distance” between the two positions of symmetri- 
cal tangency of one wire with the other, as determined by the 
narrowest possible line of light visible between the two wires. 
Finat RESULTS. 
Times of Contacts. 
Internal egress “suspected,” (a) Dec. 64 2 40™ 103° Washington mean time, 
“a * ‘ “ a a 
eden “ee ci. « ‘ 
— = Eh A ” +“ a m 92-98 sh “ 
‘ certainly past,” (d) 64 3b 1™ 23°8 
