Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1888-06-09
SOLAR HALO.
Sergeant Barwick Explains the Unusal
Phenomena.

Sergeant Barwick Explains the Unusal
Fhenomena.
The Signal Service notes on the solar
phenomena of yesterday will be found as
follows: " Between 1l:30 A. NJ. and 1:30
P. NJ. yesterday there was a bright and well
defined solar halo OF 22o radii." When the
sky is hazy, and presents dull, milky ap-
peerance, we frequently notice around the
sun or moon, cOlOTed circle having a
radius of 800, the sun occupying the center
of the circle. Such was the case Yesterday
at noon. The inner edge of the circle was
colored red, and the outer pale blue, the
colors were well defined and distinct. Such
circle is never seen where the sky is clear
The SKY within the circle was much
darker than for several degrees outside the
circle.
Whenever halos are formed about the
sun the air is filed with fine prismatic
crystals OF ice-as was the case with the
upper stratum of air yesterday-and these
crystals occupying every possible position
with respect TO the suns light. The above
described ralo is formed by the light of the
SUP shining through these CRYSTALS of ice
Since the suns rays contain all the colors
OF the spectrum, these different circles are
formed simultaneously and superpose ed.
The red projecting on the inside is unmin-
gled with any other color, and is therefore
pure; all the other colors are more or less
mingled, but in unequal proportions. so
that the outer portion of the halo is nearly
white. Such hale may be formed in
midsummer, because at a moderate eleva-
ton above the earth's surface the con-
densed vapor of the air is frozen even in
the hottest weather
h. e
mentally illustrated by crystallizing some
salt like alum upon glass plate aud then
looking through the plate at the sun or a
candle. few drops of saturated solution
of alum spread over q plate of glass will
soon cover 1t with layer of minute crys-
tais. If we place the eye close behind the
smooth side Of the glass and look at can
die, they will be seen surrounded by three
halos Of different dimensions. Each crystal
OF alum Is a regular oct6irou, with the sig
angles truncated, forming the outline of a
cube. It has, therefore, four inclined to
each other at angles of 100. 800 and HOO.
and these angles occupy every possible posi-
ton with respect to the glass plate. The
smallest halo IS formed by the refraciion of
the rings of light through g pair OF faces
inclined TO each other at an angle of
700, etc.
The temperature, wind and weather at 4
A. NJ. yesterday was $50, southeast. 6 lniIfs
per hour, and clear; IL NJ, To, nor;h. s
miles, and clear; P. NJ, $50, south. 5
miles. and fair. The averdge temperature
was 69o being 20 warmer than the normal
for that day. The highest and lowest tenn
pereture was 500 and $40, with rapidly
falling barometer during the afternoon.
Yesterday was the first time since the l6lb
of Nay that the daily average temperature
was warmer than the normal. II has been
ranging from % tO1lo cooler each day since
the above date until yesterday.
Halos and mock suns, or sun-dogs, are
supposed to indicate approaching storms,
bnt in this country they are not always a
sure forerunner of storms.
There was very fine pair Of Knock
suns" or sun. dogs, between $50 and 80
P. NJ. yesterday, with the circle around the
sun, but rather indistinct.