st principle of pseudo-logic, or our principle of
Continuity is, of course, that nothing is unique, or individual: that
all phenomena merge away into all other phenomena: that, for
instance--suppose there should be vast celestial super-oceanic, or
inter-planetary vessels that come near this earth and discharge volumes
of smoke at times. We're only supposing such a thing as that now,
because, conventionally, we are beginning modestly and tentatively. But
if it were so, there would necessarily be some phenomenon upon this
earth, with which that phenomenon would merge. Extra-mundane smoke and
smoke from cities merge, or both would manifest in black precipitations
in rain.

In Continuity, it is impossible to distinguish phenomena at their
merging-points, so we look for them at their extremes. Impossible to
distinguish between animal and vegetable in some infusoria--but
hippopotamus and violet. For all practical purposes they're
distinguishable enough. No one but a Barnum or a Bailey would send one a
bunch of hippopotami as a token of regard.

So away from the great manufacturing centers:

Black rain in Switzerland, Jan. 20, 1911. Switzerland is so remote, and
so ill at ease is the conventional explanation here, that _Nature_,
85-451, says of this rain that in certain conditions of weather, snow
may take on an appearance of blackness that is quite deceptive.

May be so. Or at night, if dark enough, snow may look black. This is
simply denying that a black rain fell in Switzerland, Jan. 20, 1911.

Extreme remoteness from great manufacturing centers:

_La Nature_, 1888, 2-406:

That Aug. 14, 1888, there fell at the Cape of Good Hope, a rain so black
as to be described as a "shower of ink."

Continuity dogs us. Continuity rules us and pulls us back. We seemed to
have a little hope that by the method of extremes we could get away from
things that merge indistinguishably into other things. We find that
every departure from one merger is entrance upon another. At the Cape of
Good Hope, vast volumes of smoke from great manufacturing centers, as an
explanation, cannot very acceptably merge with the explanation of
extra-mundane origin--but smoke from a terrestrial volcano can, and that
is the suggestion that is made in _La Nature_.

There is, in human intellection, no real standard to judge by, but our
acceptance, for the present, is that the more nearly positive will
prevail. By the more nearly positive we mean the more nea