rd to with much abated enthusiasm. Russia refused her active
co-operation in observing it, on the ground that oppositions of the
minor planets were trigonometrically more useful, and financially far
less costly; and her example was followed by Austria; while Italian
astronomers limited their sphere of action to their own peninsula.
Nevertheless, it was generally held that a phenomenon which the world
could not again witness until it was four generations older should, at
the price of any effort, not be allowed to pass in neglect.

The persuasion of its importance justified the summoning of an
International Conference at Paris in 1881, from which, however, America,
preferring independent action, held aloof. It was decided to give
Delisle's method another trial; and the ambiguities attending and
marring its use were sought to be obviated by careful regulations for
insuring agreement in the estimation of the critical moments of ingress
and egress.[782] But in fact (as M. Puiseux had shown[783]), contacts
between the limbs of the sun and planet, so far from possessing the
geometrical simplicity attributed to them, are really made up of a
prolonged succession of various and varying phases, impossible either to
predict or identify with anything like rigid exactitude. Sir Robert Ball
compared the task of determining the precise instant of their meeting or
parting, to that of telling the hour with accuracy on a watch without a
minute hand; and the comparison is admittedly inadequate. For not only
is the apparent movement of Venus across the sun extremely slow, being
but the excess of her real motion over that of the earth; but three
distinct atmospheres--the solar, terrestrial, and Cytherean--combine to
deform outlines and mask the geometrical relations which it is desired
to connect with a strict count of time.

The result was very much what had been expected. The arrangements were
excellent, and were only in a few cases disconcerted by bad weather. The
British parties, under the experienced guidance of Mr. Stone, the late
Radcliffe observer, took up positions scattered over the globe, from
Queensland to Bermuda; the Americans collected a whole library of
photographs; the Germans and Belgians trusted to the heliometer; the
French used the camera as an adjunct to the method of contacts. Yet
little or no approach was made to solving the problem. Thus, from 606
measures of Venus on the sun, taken with a new kind of heliometer at