Page:Letters from New Zealand (Harper).djvu/304

272, we tackled the general facts of the problem, and planned to observe the transit of the planet across the sun, which occurs once in a hundred years, and eight years later again takes place. It offers the best known means of ascertaining the sun's distance from the earth, and from that the relative distances of all the planets in our system can be deduced with fair accuracy. For this purpose simultaneous observations must be taken at stations distant as far as possible from each other, as, for example, Great Britain and New Zealand. The British Government sent to New Zealand a well-equipped expedition, consisting of Major Palmer, well known for his work in Palestine, Lieutenant Darwin, and a staff of subordinates from Greenwich, with all necessary instruments. Major Palmer established himself in two places, at Burnham, near Christchurch, and in Otago. Knowing, as we did in Westland, that in December it constantly happened that the skies were clear whilst overcast in Canterbury, and that so much depended on this, we suggested to Major Palmer that he should send us competent observers and instruments, in view of failure in Canterbury. Unable to do this, he gave us full directions, and, as we had some good chronometers, instructed us how to rate them with his sidereal clock at Burnham, so that he might know the exact time of any observations we might make.

The day was cloudless: our task was to observe the moment of the planet's ingress on the sun's disc, and of its egress on the other side,—this to half a second. On the beach we had erected an iron observatory shed, O'Connor at the telescope, myself and three others ready, at his call, to note the exact time of it; two calls, the first at the moment when Venus just touches