TRANSIT OF VENUS. 327 
in alt. azimuth, on a strong tripod, and has very smooth acting 
slow-motion gearing. To secure greater steadiness the legs 
were fixed to a horizonal triangle of timber, firmly attached to 
piles driven into the ground. Its optical performance in the fine 
atmosphere of this inland district was extraordinarily perfect, 
and high powers of 300 and 400 diameters could generally be 
used without producing blurring or imperfect definition, while 
the “rice grains” and other characters of the sun’s surface were 
quite distinct with much lower powers, The telescope was fur- 
nished with a first surface reflecting prism for solar work, sup- 
plied by the maker, and also neutral tint glasses of various 
shades ; but as these were all found to be too dim, slips of the 
optical glass, known as “London smoke,” were used instead. 
Two or three thicknesses were sufficient, the first surface being 
placed in absolute contact with the lens nearest to the eye. The 
time-keeper was the full-size chronometer No. 7430, by Thos. 
Russell, London, beating half-seconds, with a chronometer watch 
for daily comparison. Before leaving Wellington the chrono- 
meter had no sensible rate of error; but during the journey it 
appears, from the appended records, to have lost about 35 se- 
conds, and after its arrival at Clyde to have acquired a steady 
gaining rate of about 05 per day. The chronometer was screwed 
down to stakes driven into the ground through a hole cut in the 
floor, so that it might be quite free from vibration. Close beside 
it, on a slightly higher level, were the contact keys of the tele- 
graph instruments, so that they could be manipulated while the 
eye was vertical over the seconds hand. 
The telegraph apparatus had a line battery of 35 cells, and 
two local circuit batteries of 15 cells each; but provision was 
made for joining in one of the latter to the line battery for dis- 
tant signals when required. 
One local circuit was for working either with the relay or by 
a contact spring when observing with the telescope, and the 
other was for working the second pecker of the chronograph, 
which was a double instrument, having two independent peckers 
marking on the same tape. The velocity of the tape gave about 
34 of an inch distance between the mark for each second. 
The telegraph instruments were furnished and arranged ready 
for use by Dr. Lemon, and the fitting up of the chronograph and 
batteries was done by my assistant, Mr..E. Ashcroft. They were 
in good working order in less than a day, and never gave the 
slightest trouble afterwards. Mr. Henry, the telegraphist at 
Clyde, conducted all the communications most efficiently, and 
on some occasions had to exercise much skill and patience to 
secure the integrity of the time signals received. 
The Observation. 
The 6th December, 1882, was a splendid day, clear and 
bright, with a cool southerly breeze. At early morning, and 
again in the afternoon, the programme for the observation was 
