--My preparations for the Transit of Venus have
respect only to eye-observation of contact of limbs. With all the
liabilities and defects to which it is subject, this method possesses
the inestimable advantage of placing no reliance on instrumental
scales. I hope that the error of observation may not exceed four
seconds of time, corresponding to about 0.13" of arc. I shall be very
glad to see, in a detailed form, a plan for making the proper measures
by heliometric or photographic apparatus; and should take great
interest in combining these with the eye-observations, if my selected
stations can be made available. But my present impression is one of
doubt on the certainty of equality of parts in the scale employed. An
error depending on this cause could not be diminished by any
repetition of observations."--After referring to the desirability of
vigorously prosecuting the Meteorological Reductions (already begun)
and of discussing the Magnetic Observations, the Report concludes
thus: "There is another consideration which very often presents itself
to my mind; the waste of labour in the repetition of observations at
different observatories..... I think that this consideration ought not
to be put out of sight in planning the courses of different
Observatories.
Pages:
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474