1875.] The Late Transit of Venus. 179 
well with those made in Egypt and at Roorkee. The 
German observations in the Auckland Isles will combine 
admirably with the German observations in Egypt. 
Before passing to the operations by other methods, it may 
be well to consider the general Delislean results, and the 
lessons they teach us as to future operations. It is, in the 
first place, certain, that if only Delislean operations had been 
provided for, as in the original programme, the measure of 
success achieved would have been very far from satisfactory. 
Early ingress does not appear to have been well observed, 
and Janssen’s method failed, so that the complete ingress 
operations are to some degree imperfect. The English special 
operations for observing egress have completely broken down 
through the failure in New Zealand. The success of 
the Germans is a strong point, but one success counts for 
little in a process where everything depends on reducing the 
final error through the mumber of successful observations. 
It is to be noted that the German success results entirely 
from the fact that the Auckland Isles were occupied. 
These are among the island groups to which I direé¢ted 
attention in 1869. Chatham Island, from which we hope 
to hear of good American egress observations, was another— 
rejected by the Astronomer Royal, because, by a miscalcu- 
lation, he set the solar elevation 7° too low. Campbell 
Island, where the French have a station (not yet reported 
from), was yet another of these islands. All of these were 
specially named by me as suitable for applying the Delislean 
method at egress, and also for observing the whole transit. 
Their occupation by America, France, and Germany, and 
the success of the Germans (even though we should not 
learn that the Americans and French had also been success- 
ful), sufficiently justify my suggestions, and more than 
meet the comments made on these suggestions by official 
persons. On the other hand, the partial failure of the 
English Government operations in no sense supports my 
position, except in so far as to justify the anxiety I ex- 
pressed. Bad weather might equally have thwarted the 
arrangements I proposed, which other nations carried out. 
Turning now to Halleyan and mid-transit operations, we 
have a series of excellent results to consider. 
In the first place, let us examine the northern successes. 
At Nertschinsk, where the duration fell short of the mean 
by fully 15} minutes, the Russians observed the whole 
transit with excellent telescopes, and obtained a number of 
measures and photographs. This success is particularly 
gratifying, as Nertschinsk was the best of all stations for 
