The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1900-05-06
MEASUREMENT OF TIME.
The Julian and Gregorian Calendars
Reason For Leap Years.
(St. Louis GIobe-Democrat)

Professor C. W. Pritchett of the Morri-
son observatory at Glasgow, No, has
collated some interesting facts concerning
the question of leap year and the author
ity of the calendar which the unscientific
reader viii find easy TO comprehend.
In the first place he calls attention TO
the fact that the calendar is purely arti-
hclal, conventional and arbitrary. 1t was
the custom of the pontiffs on the first
day OF the month to call out the people
to announce judicial and sacred days, and
so from the Greek word ''kaleia"-tO call
came the word.
1t Is the design of the modern calendar
to distribute time into periods, SO as to
subserve the purposes of society. The
first requisite is the establishment of
convenient and unvarying unit of time
measure. Nature herself does not give
this standard unit of measure. 1t IS pure
~ conventional and is the gift of astron-
omy to the world. 1t is the mean solar
day. as distinguished from the apparent
solar day. and from the sidereal or star
day This day commences at midnight on
one day, and ends at the following mid
night. This is the civil day recognized in
all civilized countries.
Our second unit of time expressed in
terms of the standard unit is the tropical
year, or the interval between two sue
ceSSive returns of the true suns center
to the Vernal equinox expressed in mean
solar days. This unit is so nearly inVari-
able that it only diminishes .595 of a sec
Ond in 100 years. The latest value deter
mined for it is 365 days hours As minutes
46.045 seconds, or 365-2421996 days. 1t is easy
TO see that the mean solar day is not
contained in the tropical year an exact
number of times, but society cannot take
account of a fraction of a day to fill out
every year, and this fact, together with
the fact that the units are not common
surate, constitutes the reason for leap
years; 365 mean solar days are too small
and 366 too long to fill exactly the tropical
year. The problem then is to find a year
of mean or average length, which shall
differ from the tropical year by a guam
tty as small as practica bic. By a mathe-
matcal process q series of Approximate
fractions may be found for the decimal
.242l99o, each approaching nearer to the
true value until the limit is reached.
julius Caesar was the first to introduce
this system of INTERPOLATION, and because
of the fact that the calendar had fallen
into such error that the civil year diff
feTed from the true equinox three months,
Caesar decreed that after three successive
consist of $50 days. He changed the be-
ginning Of the year from the winter sol
stice to Jan. I. He ordained that the odd
months should have thirty-one days and
the even thirty, except February. which
was to have tWenty-nine and leap year
thirty. But when Augustus came TO the
throne he desired that his moiith. August.
should have as many days as July. named
in honor of his uncle, so one day was
taken from February and given to
August.
Easter Sunday, according to the Coun-
the fourteenth day of the PaschS1 moon,
the moon whose fourteenth day falls on
or follows the 2lst of March, the veTnal
equinox. Pope Gregory, in order to recon-
Gle the church and civil year. ordered ten
days to be stricken out of the calendar in