Easter of its variable character, and of fixing
it invariably, on the first Sunday in April, for
instance. As it is, in consequence of the rule
in force, it results that this first full moon
can never happen before the twenty-first of
March, nor the Feast of Easter before the
twenty-second. Our century has as yet
offered only a single example of Easter's
happening the first day after the March full
moon, which was in eighteen hundred and
eighteen, when Easter fell on the twenty-
second of March.

The other limit—the latest date at which
this same feast can possibly be celebrated, is
the twenty-fifth of April. In fact, if the full
moon happens on the twentieth of March, it
will not be the Paschal moon; the proper
Paschal moon will shine on the eighteenth
of April; and, if that day turns out to be a
Sunday, Easter cannot be celebrated till the
Sunday following, the twenty-fifth of April.
As instances of the two extremes, the Feast of
Easter occurred on the twenty-second of
March, in fifteen hundred and ninety-eight, in
sixteen hundred and ninety-three, in seventeen
hundred and sixty-one, in eighteen
hundred and eighteen, and will occur in
two thousand two hundred and eighty-five.
It has fallen on the twenty-fifth of April,
in sixteen hundred and sixty-six, in seventeen
hundred and thirty-four, and will so fall again
in eighteen hundred and eighty-six, in nineteen
hundred and forty-three, in two thousand
and thirty-eight, and in two thousand
one hundred and ninety, which is quite long
enough for us to look forward to. From
the twenty-second of March to the twenty-
fifth of April, both inclusive, there are
five-and-thirty days. Easter therefore can
occupy five-and-thirty different places in the
calendar.

This present lagging Easter, happening on
the twenty-fifth of April, is quite an exceptional
case; nor is the extreme limit often
nearly approached. In eighteen hundred and
fifty-one, Easter fell on the twentieth of
April; in eighteen hundred and ten, in eighteen
hundred and thirty-one, and in eighteen
hundred and thirty-two, on the twenty-
second; in eighteen hundred and forty-eight,
it did not come till the twenty-third. In
eighteen hundred and fifty-nine, the current
year, Easter will not happen till the twenty-
fourth of April. The reason is this: We
have seen that, according to the rule of the
Council of Nicæa, Easter ought to be celebrated
on the Sunday which follows the day
of the first full moon happening after the
twentieth of March. Now, in eighteen hundred
and fifty-nine, the moon is full two days
before the twentieth of March, namely, on
the eighteenth; it is therefore on the Sunday
after the following full moon that the Feast
of Easter ought to be celebrated. This new
full moon will happen on the seventeenth
of April. But as that very day is precisely
a Sunday, the celebration of Easter must be
put off till the following Sunday, April the
twenty-fourth.

The persons who originally adopted the
rule by which Easter Day is fixed, held
notions respecting the movements of the sun
and moon which have not been confirmed by
subsequent observations; nevertheless, the
Paschal moon is still determined according
to these preconceived ideas, by making use of
periods which you will hear about shortly,
regulated by the Golden Number, the Epact,
and other contrivances. This Paschal moon,
this conventional satellite, may arrive at the
full a day or two before or after the real
moon or the mean astronomical moon, which
has given rise to frequent complaints on the
part of the public, who are not generally
aware that Easter is regulated by a fictitious,
imaginary moon, and not by the real moon
which shines in the heavens. On this account,
the vulgar are apt to charge with ignorance,
or at least with inattention, the astronomers
who stupidly make them celebrate Easter a
month too late, as the testimony of their own
eyesight informs them to be the case.
Nevertheless, astronomers are not in the least
responsible for such errors, or rather for such
irregularities. Thus, in seventeen hundred
and ninety-eight, although Easter ought to
have been kept on Sunday the first of April,
according to the actual state of the moon, it
was not celebrated till the Sunday afterwards.
A similar instance occurred in eighteen
hundred and eighteen. If the visible
moon had been consulted, she would have
ordered the celebration of Easter on the
twenty-ninth of March; the festival was
observed on the twenty-second instead, in
obedience to the fictitious moon. The
theoretical time when the real moon is a new
moon, depends on astronomical tables which
are continually brought nearer and nearer to
perfection; the epoch of the celebration of
Easter would not by this method be
determined beforehand with certainty; the
correction of an error of half a minute of time
might cause the festival to be deferred for a
week. Thia inconvenience completely justifies
the choice of what is called an ecclesiastical
moon for the regulation of religious
rites. To these peremptory reasons may be
added another, which can scarcely be allowed
to have equal value. According to Clavius,
the idea is not to be entertained of regulating
Easter by the real moon; because, as he
wisely remarks, the festival would, in that
case, be held at the same time with the
Easter of the Jews, which would be highly
improper, nay indecent.

And now for the practical application of
the rules of ecclesiastical astronomy. In
the year four hundred and three before the
Christian era, the Greek astronomer, Meton,
discovered that at the end of nineteen lunar
years, comprising two hundred and thirty-five
lunations, the same phases of the moon recur
at the same epochs, because the sun and the