INTRODUCTION. v 



" approaching Transit of Venus will depend to a great extent on observations 

 " being made in the Southern Hemisphere, to compare with those which are 

 " already amply provided for in Siberia and China, it is in the opinion of 

 " the Board of Visitors very desirable that parties suitably equipped be 

 " despatched to the South, in the hope of finding some additional practicable 

 " places at which the entire duration of the Transit may be observed." The 

 Admiralty, in reply to the Board of Visitors, adverted to the voyage of the 

 " Challenger," and to the prudence of waiting for reports from that ship. I 

 may here state that subsequent information thus obtained justified the entire 

 rejection of the Heard Islands, on account of the extreme uncertainty of 

 communication (the Crozet Islands had been previously rejected for the same 

 reason), and indicated unexpected facilities in the adoption of the southern 

 part of Kerguelen Island. 



On 1874, January 24, I placed before the Admiralty a general statement of 

 arrangements, and on March 11, Captain Tupman was first put in commu- 

 nication with the Accountant-General, the Director of Transports, and the 

 Hydrographer, for management of the expedition when afloat and of its 

 money-affairs. On May 4, in reply to a letter of the Admiralty, I offered my 

 strong testimony to the value of Captain Tupman's services. 



The greater portion of the observing parties sailed in the early part of 

 summer ; that for Egypt naturally much later than the others. Time, 

 however, was occupied by the Egyptian party at Greenwich in practice for 

 the operations with the long submarine telegraph. The several parties 

 returned at different times : the breaking up of their residences depending, 

 for the most part, on the completion of operations for longitude. On those 

 points information will be found in the several Parts of the following work. 



Some advance had been made by each party in the orderly record and 

 partial reduction of their observations. As soon as Captain Tupman returned, 

 all the observers were placed under his superintendence, at the Royal 

 Observatory, for completing their share of the reductions and for measure 

 of the photographs. As the work of each observer was finished, he was 

 discharged from the service. The last was Lieut. Neate, R.N., from 

 Rodriguez ; his return was late, and his calculations voluminous ; and they 

 were not finished before October 1876. 



From this time every calculation was subjected to the severe examination 

 of Captain Tupman. 



On 1877, April 14, a member of the House of Commons gave notice to the 

 First Lord of the Admiralty of his intention to inquire, on April 19, when 



