prognostication, which may justify expensive
illustration, is yet to arrive.

The reader will find in the general plates representations of several
kinds of cirri. They are delicate, always white, more or less fibrous, and
form in the upper part of the trade or the adjoining atmosphere above it.
Their character and elevation should be studied, and the observer should
be careful to distinguish which is the most elevated. Not unfrequently it
may seem, to a hasty observer, that the cirrus is below the cirro-stratus
or forming stratus. But the genuine cirrus never is. It forms near, and
above, the point of congelation, and is often composed of crystals of ice
or snow. If they fall, they melt and evaporate, when there is no storm,
before reaching the earth. Aeronauts have met with them and their crystals
when there was no fall of moisture at the surface of the earth; and the
angles of reflection exhibited by halos and other optical phenomena which
form in them, enable us to detect their crystallization and the form of
it.

They are produced by electric changes which condense the vapor, and the
coldness of the air at that elevation freezes it at the _instant of its
condensation_.

Congelation is crystallization, and all crystallization is electric, or
magneto-electric. The snow-flakes differ in form and size according to the
suddenness of the condensation, the amount of moisture condensed, the
polarity of the strata through which they pass, and their consequent
attraction and adhesion to each other.

The connection of electricity with these formations of cirri has
frequently been admitted, and it is perfectly obvious that the long
fibrous bands, shooting from horizon to horizon, could not be formed by
commingling of currents any more than the perfectly isolated, distinct,
enlarging-outward cumulus hail-storm, could be so formed. Cirri form at
the line of meeting, between the trade and the upper atmosphere, and in
one or the other, or both, very much according to the season, and the
suddenness with which storms are produced. These often _induce_ a layer of
cirro-stratus or stratus at the lower line of the counter-trade, and in
the surface-atmosphere, which precipitates; and this operation is clearly
discernible, and very frequently, before gentle rains. Condensation in the
whole body of the trade is usually in the form of turbidness or mistiness,
a bank or incipient stratus, without cirri.

It seems matter of astonishmen