lines and also
confirm the drawings of observers.

Professor Schiaparelli, who has been appealed to on the subject, still
maintains the objectivity of the canal lines which he was the first to
discover, and repudiates the suggestion that the new photographs supply
any evidence against them. He remarks that during the last thirty years
many other astronomers, using more perfect telescopes than his, have
observed and drawn these canal lines, and have taken photographs which
reproduce an identical disposition of the lines. He adds that a
collective illusion on the part of so many astronomers is impossible,
and that the photographs which do show the canals cannot be illusions.

Professor Lowell controverts M. Antoniadi's claim to have proved that
the lines are non-existent, and that the only markings are small
separate shadings which are illusively seen as lines. He points out that
what M. Antoniadi has seen is exactly what would be seen when using a
very large telescope, and that it indicates poor seeing instead of good
definition. He remarks that when using such large instruments, which are
so much more affected by atmospheric conditions than smaller ones, the
diffraction rings round a star (which should appear as complete
concentric circles) begin to waver, then break up into fragments--a sort
of mosaic--and finally end in an indiscriminate assemblance of points.
In certain kinds of bad seeing the parts may seem quite steady, but the
fact that the mosaic exists is proof positive of poor seeing. What
happens to the rings in such circumstances must also happen to fine
lines! the mosaic effect seen by M. Antoniadi is therefore "the exact
theoretic effect that a large aperture should produce on continuous
lines, such as the canals, and always does produce in the case of the
rings in the image of a star!"

It has been stated that Professor Lowell had admitted the illusory
nature of the canal lines. His reply, however, is emphatic: "I have
never made any retractation as to the reality and geometricism of the
canals; they are marvellous beyond conception, and are only doubted by
those who never observed the planet itself sufficiently well."

Seeing an announcement that Professor Lowell had arrived in England for
the purpose of lecturing on "Planetary Photography" at the Royal
Institution of Great Britain, M'Allister and I made up our minds to be
present at the lecture, a resolution which, I am glad to say, we carried
into e