VENUS ON THE SUN'S FACE. 6$ 



be too low ; but here, again, a more exact consideration 

 of the circumstances of the transit has led astronomers 

 to the conclusion that the sun will be quite high enough 

 at this station. 



The Kussian observers are principally concerned with 

 the observation of the retarded end of the transit, nearly 

 all the best stations lying in Siberia. But there are 

 several stations in British India where this phase can 

 be very usefully observed; and doubtless the skilful 

 astronomers and mathematicians who are taking part 

 in the survey of India will be invited as at the time 

 of the great eclipse to give their services in the cause 

 of science. Alexandria, also, though inferior to several 

 of the Indian stations, will probably be visited by an 

 observing party from England. 



It will be seen that England will thus be called 

 on to supply about half-a-dozen expeditions to view the 

 transit. All of these will be sent out in pursuance of 

 Delisle's mode of utilising a transit, so that, for reasons 

 already referred to, it will be necessary that they 

 should be provided with instruments of the utmost 

 delicacy, and very carefully constructed. 1 They will 

 have to remain at their several stations for a long time 

 before the transit takes place several months, at least 

 so that they may accurately determine the latitude of 

 the temporary observatories they will erect. This is a 

 work requiring skilled observers and recondite processes 



1 It is held to be of the utmost importance that all the observing 

 parties should use similar telescopes. 



