MAY, 1897. MONTHLY WEATHER REVIEW. 207
search light which renders them visible is an invaluablt
assistant. A year ago some accounta were published relativt
to the cloud effects on Mount Low and Pasadena. According
to these accounts Mount Low is about 15 miles north-north.
east from Loa Angeles and about 6 miles in a straight lint
from Paradena. When the beam of light fell upon the bodiei of clouds they at once became luminous, so that all the de. taile of motion were visible; when the beam fell upon tht
falling rain the great cone of light glowed like molten metal
Distant clouds moving up the canyons were searched out and
made to glow as if in the midday sunshine. It seems as ii the formation and motion of fog and cloud at nighttimt
conld be advantageously studied by means of the search
light. The height a t which fog first forms, and its gradual extension upward and downward during the night, would be
a vmy interesting and profitable inveatigation.
WATERSFOUTS OFF LONG ISLAND.
On April 9 when the schooner George M. Grmt was within
B few knots of Montauk Point, the sea, which had been heavy
all along the Long Island coast from Fire Island, rapidly be.
came the roughest that Captain Pelton had ever seen. It Waf
about eight bells, or 4 p. m., and thick weather had prevailed all day. During a temporary lift in the clouds Captain Pel-
ton and his crew saw ahead four immense waterspouts. Three
of them were a t a comfortahledistance, but the fourth passed
by to starboard not an eighth of a mile from the schooner, Captain Pelton says that the noise made by the spout as it
whirled by the vessel was like that made by an immense corn-
sheller.
WATERSPOUT, ULOUDBURST, OR TOWADO.
These three terms are often used indiscriminately when it
would be easy to make a clear distinction between them. The
Cleveland World of April 1 reports that “ a waterspout on
March 31 at Pam, Ill., threw a train of five cars and engine from the track of the Illinois Central.” It does not appear
likely that the damage here mentioned was done by wind ; we
may, therefore, infer that we have not to do with a tornado.
A waterspout a t sea is, according to all established usages in
the English language, a different phenomenon from a heavy
rain. Rain often accompanies a waterspout, but is not the
prominent and characteristic feature. I n the present case there could have been no waterspout properly speaking be- cause the phenomenon occurred over the dry land of the in-
terior of the continent. The daily weather map shows that the conditions were favorable for the formation of aevere
rains, thunderstorms, cloudbursts, and possibly tornadoes over Illinois on the afternoon of March 31 ; in fact a tornado was
reported in Arkansas, but not waterspouta properly so-called.
The use of the word “ waterspout,” when the writer really
means onlya heavy rain and wind, is not to bo recommended.
Such rains and winds are characteristic of thuiiderstorms and so-called “ cloudbursts.” I n the present caae it is likely that
rain did not alone do the damage that is reported ; a flooded
track and a strong current of water would be needed to throw an engine from the track, or possibly the flood caused by the
rain had undermined the track and thus indirectly caused
the derailment. I n general, in such caaes as this it would be
more proper to omit the words “ waterspout ” and ‘‘ cloud- bhrst.” If the train was thrown from the track, or lifted
from the track, as the headlines of the above article had it, this must have been due to a severe storm, but certainly not
to a “waterspout properly so called.
CHaRaCTER OF THE SKYLIGm.
It is generally recognized that the influence of the sun-
light and diffused skylight on the assimilation and growth of
plank is brought about, first, by the heat that warms the
earth and promotes the rise of the sap and, second, by the
chemical action that is brought about by certain portions of
the solar spectrum or more properly by radiations of specific
wave lengths which fall upon the leaves of the planta and
determine the formation of chlorophyll. When planta are cultivated under tho influence of artificial lights, or in por- tions of the earth where the sunlight is obscured by cloud
and fog: their development is usually slower, and they often-
times fail altogether to produce a satisfactory sap or crop, or
mature seed. This failure is reasonably attributed to the nature of the light arid especially to the relative abundance
of the radiations that produce favorable chemical clianges as
compared with those that produce undesirable changes. Any investigation into the influence of climate on plants and crops and any effort to cultivate plants by artificial light
must take into account the relative energies transmitted in
different portions of the spectrum. This distribution of
energy with wave length is extremely irregular when the flame is produced by burning simple substaiices, as is shown
by the fact that the spectrum is generally a aeries of alter-
nating bright and dark or warm and cold spaces, but is much
more regular when the radiation emanates from incandeacent masses of solids before they evaporate into the gaseous con-
dition. The distribution of energy throughout the spectrum is also greatly affected by the reflection from any surface;
especially is this true in the case of the blue light of the sky,
which is apparently a species of selective reflection from the
minutest particles of aqueous vapor and which, notwithstand- ing ita visual feebleness, is yet a matter of the greatest impor-
tance to agriculture. The total amount of eneqgy received
by any plant from the whole vault of the blue sky will in
hazy weather equal that received directly from the sun and in the case of a thin layer of cloud or fog when the sun is in-
visible and the direct radiation therefore zero, the indirect diffused radiation may still be a large quantity. This latter
consideration suffices to explain why many planta flourish
in a foggy and cloudy climate and in shady places where the
direct sunlight never penetrates. The total energy involved in the molecular vibrations that
constitute radiation is not shown by its effect in producing
light or heat or chemical actions; these are but some of the modes in which a portion of that energy becomes appreciable
to us. This radiant energy is conveyed from point to point by the mediation of the ether, and the ether can only be-
some appreciated by its action on the so-called ponderable
matter. It is probable that the energy involved in the move- menta of the ether is far greater than that which is made
measurable by its visual, chemical, or thormsl results, for
there are still other results acconiplished by it, as shown by the phenomena of electricity, magnetism, and gravitation.
The following table is quoted from a paper in the Aiiaalen
ier P h y d m d Chemie, Vol. LIII, by Koettgen, who has meas-
ired the relative intensity of the light in the different parts If the spectrum from a large variciy of lamps and burning
iubstances. Her measures of tho sunlight and skylight par-
Jcularly interest the ineteorologist and agriculturist. They
were made in the first half of August, 1893, near Berlin, Ger- nany, in latitude N. 52O. At this seaaon and place the maxi-
num midday altitude of the sun varies from 5 6 O on August 1
KJ 62O on Auguat 15. The measurements were made by di- wcting the vision toward the blue skylight at a considerable
rltitude above the horizon, and probably in the northern por- ,ion of the sky, although that ia not specifically stated. The mesults are given in the first column. When directed toward
m overcast sky covered by an apparently uniform thickness
)f cloud, the measurements given in the fourth column were
Ibtained, and when directed toward the shining white side of
b cumulus cloud, thoae in the fifth column. When directed
award the sun itaelf, the measurementa giveu in the sixth
tnd seventh columns were obtained. The figures given in