More Science from an Easy Chair

by Sir E. Ray Lankester

Deception in the world of reality is very different from make-believe, and a terrible thing. To the child—deception in regard to real things, whatever excuses adults may put forward in its defence, is well-nigh unforgivable. To be one who never says "it is" when it is not, nor "it will be" when it will not be—that is to be a friend on whom a child rests in perfect trust and happiness.

What have these thoughts to do with the New Year? Merely this, that it is not only with and for children that we make-believe at this season—we all of us, more or less, indulge in a make-believe about the New Year. As the clock strikes its twelve notes at midnight on December 31st, and all the bells of a great city are heard hovering in the air, sending forth their sweet sounds from far and near into the fateful night, there are few of us who have not a feeling that a great event has occurred. A physical change has set in—the Old Year is dead and gone, and the New Year, something tangible, which you can let in at the door or the window—has just come into being, and is there waiting for us. We are, of course, indulging in "make-believe," for there is no New Year, with any natural, noteworthy thing to mark its commencement, starting at midnight on December 31st. New Years begin every day and hour, and it is by no means agreed upon by all nations of the earth to pretend that the 1st of January is the critical day which we must regard as that portentous epoch, the beginning of the New Year. This choice of a day was made by the Romans, and that wonderful man Julius Cæsar had a great deal to do with it; modern Europe adopted his arrangement of the year or calendar. But the Jews have their own calendar and their own New Year's Day, which varies from year to year, from our September 5th to our October 7th. It is, however, to them always the first day of the month Tishri, and the first day of their new year. The Mahomedans took the date of the flight of Mohammed from Mecca to Medina—the night of July 15th, 622 a.d.—as the commencement of their "era," and its anniversary is the first day of their month Muharram and the first day of their year—their New Year's Day. As, although they reckon twelve months to the year, their months are true lunar months, and are not corrected as are those in use by us (as I will explain below); their year consists of 354 days 8 hours, and so does not run parallel to our year at all. Their New Year's day, which began by being our July 16th, was in the next year coincident with our July 6th, then in three successive years it occurred on different days of June, and so on through May, April, and the preceding months, so that in thirty-two and a half of our years their New Year's Day has run through all our months and comes back again to July.

So much for New Year's Days; they are arbitrary selections, and though the Roman New Year's Day, or January 1st, has been precisely defined and fixed by the determination by astronomers of the position of the earth on that day in its revolution around the sun, yet the original selection of January 1st for the beginning of the year seems to have been merely the result of previous errors and negligence in attempting to fix the winter solstice (which now comes out as December 22nd). This is the day when the sun is lowest and the day shortest; after it has passed the sun appears gradually to acquire a new power, and increases the duration of his stay above the horizon until the longest day is reached—the summer solstice (June 21st). Julius Cæsar took January 1st for New Year's Day as being the first day of a month nearest to the winter solstice. The ancient Greeks regarded the beginning of September as "New Year."

Were mankind content with the measure of time by the completion of a cycle of revolution of the earth around the sun—that is the year—and by the revolution of the earth on its own axis—that is the day or day-night ([Greek: nychthêmeron]) of the Greeks—the notation of time and of seasons would be comparatively simple. No one seems to know why or when the day was first divided into twenty-four hours, nor why sixty minutes were taken in the hour and sixty seconds in the minute. The ancient astronomers of Egypt and China, and their beliefs in mystical numbers, have to do with the first choosing of these intervals in unrecorded ages of antiquity (as much as 2000 or 3000 b.c.). The seven days of the week correspond to the five planets known to the ancients, with the addition of the sun and the moon. But the Greeks made three weeks of ten days each in a month. The true year—the exact period of a complete revolution of the earth around the sun—is 365 days 5 hours 18 minutes and 46 seconds. It was measured with a fair amount of accuracy by very ancient races of men, who fixed the position of the rising sun at the longest day by erecting big stones, one close at hand and one at a distance, so as to give a line pointing exactly to the rising spot of the sun on the horizon, as at Stonehenge. They recorded the number of days which elapsed before the longest day again appeared, and they marked also the division of that period by the two events of equally long sunlight and darkness—the spring and the autumn "equinox." It is obvious that if they took 365 days roughly as the period of revolution they would (owing to the odd hours and minutes left out) get about a day wrong in four years, and it was the business of the priests—even in ancient Rome the pontiffs were charged with this duty—to make the correction add the missing day, and proclaim the chief days of the year—the shortest day, the longest day, and the equinox-days of equal halves of sunshine and darkness. In ancient China, if the State astronomer made a wrong calculation in predicting an eclipse he was decapitated.

It is easy to understand how it became desirable to recognise more convenient divisions of the year than the four quarters marked by the solstices and the equinoxes. Various astronomical events were studied, and their regular recurrence ascertained, and they were used for this purpose. But the most obvious natural timekeeper to make use of, besides the sun, was the moon. The moon completes its cycle of change on the average in 29-1/2 days. It was used by every man to mark the passage of the year, and its periods from new moon to new moon were called, as in our language, "months" or "moons," and divided into quarters. It is, however, an awkward fact that twelve lunar months give 354 days, so that there are eleven days left over when the solar year is divided into lunar months. The attempt to invent and cause the adoption of a system which shall regularly mark out the year into the popular and universally recognised "moons," and yet shall not make the year itself, so built up, of a length which does not agree with the true year recorded by the return of the rising sun to exactly the same spot on the horizon after 365 days and a few hours, has been throughout all the history of civilised man, and even among prehistoric peoples, a matter of difficulty. It has led to the most varied and ingenious systems, entrusted to the most learned priests and state officers, and mostly so complicated as to break down in the working, until we come to the great clear-headed man Julius Cæsar.

In the very earliest times of the city of Rome the solar year, or complete cycle of the seasons, was divided into ten lunar months covering 304 days, and it is not known how the remaining days necessary to complete the solar revolution were dealt with, or disposed of. The year was considered to commence with March, probably with the intention of getting New Year's Day near to the spring equinox. The Celtic people and the Druids, with their mistletoe rites, kept New Year also at that time. The ten Roman months were named Martius, Aprilus, Maius, Junius, Quintillis, Sextilis, September, October, November, December. In the reign of the King Numa two months were added to the year—namely, Januarius at the beginning and Februarius at the end. In 452 b.c. February was removed from the end and given second place. The Romans thus arranged twelve months into the year, as the ancient Egyptians and the Greeks had long before done. The months were made by law to consist alternately of twenty-nine and of thirty days (thus keeping near to the average length of a true lunar cycle), and an odd day was thrown in for luck, making the year to consist of 355 days. This, of course, differs from the solar year by ten days and a bit. To make the solar year and the civil or calendar year coincide as nearly as might be, Numa ordered that a special or "intercalary" month should be inserted every second year between February 23rd and 24th. It was called "Mercedonius," and consisted of twenty-two and of twenty-three days alternately, so that four years contained 1465 days, giving a mean of 366-1/4 days to each year. But this gave nearly a day too much in each year of the calendar (as the legal or civil year is called) as compared with the true solar year, agreement with which was the object in view. So another law was made to reduce the excess of days in every twenty-four years. Obviously the superintendence of these variations, and the public declaration of the calendar for each year, was a very serious and important task, affecting all kinds of legal contracts. The pontiffs to whom the duty was assigned abused their power for political ends, and so little care had they taken to regulate the civil year and keep it in coincidence with the solar year that in the time of Julius Cæsar the civil equinox differed from the astronomical by three months, the real spring equinox occurring, not at the end of what was called March by the calendar, but in June!

Julius Cæsar took the matter in hand and put things into better order. He abolished all attempt to record by the calendar a lunar year of twelve lunar months; he fixed the length of the civil year to agree as near as might be with that of the solar year, and arbitrarily altered the months; in fact, abandoned the "lunar month" and instituted the "calendar month." Thus he decreed that the ordinary year should be 365 days, but that every fourth year (which, for some perverse reason, we call "leap" year) should have an extra day. He ordered that the alternate months, from January to November inclusive, should have thirty-one days and the others thirty days, excepting February, which was to have in common years twenty-nine, but in every fourth year (our leap year) thirty. This perfectly reasonable, though arbitrary, definition of the months was accompanied by the alteration of the name of the month Quintilis to Julius, in honour of the great man. Later Augustus had the name of the month Sextilis altered to Augustus for his own glorification, and in order to gratify his vanity a law was passed taking away a day from February and putting it on to August, so that August might have thirty-one days as well as July, and not the inferior total of thirty previously assigned to it! At the same time, so that three months of thirty-one days might not come together, September and November were reduced to thirty days, and thirty-one given to October and December. In order to get everything into order and start fair Julius Cæsar restored the spring equinox to March 25th (Numa's date for it, but really four days late). For this purpose he ordered two extraordinary months, as well as Numa's intercalary month Mercedonius, to be inserted in the year 47 b.c., giving that year in all 445 days. It was called "the last year of confusion." January 1st, forty-six years before the birth of Christ and the 708th since the foundation of the city, was the first day of "the first Julian year."

Although Julius Cæsar's correction and his provisions for keeping the "civil" year coincident with the astronomical year were admirable, yet they were not perfect. His astronomer, by name Sosigenes, did his best, but assumed the astronomical year to be 11 min. 14 sec. longer than it really is. In 400 years this amounts to an error of three days. The increasing disagreement of the "civil" and the "real" equinox was noticed by learned men in successive centuries. At last, in a.d. 1582, it was found that the real astronomical equinox, which was supposed to occur on March 25th, when Julius Cæsar introduced his calendar (not on March 21st, as was later discovered to be the fact), had retrograded towards the beginning of the civil year, so that it coincided with March 11th of the calendar. In order to restore the equinox to its proper place (March 21st), Pope Gregory XIII directed ten days to be suppressed in the calendar—of that year—and to prevent things going wrong again it was enacted that leap-year day shall not be reckoned in those centenary years which are not multiples of 400. Thus Pope Gregory got rid of three days out of the Julian calendar, or civil year, in every 400 years, since 1600 was retained as a leap-year, but 1700, 1800 and 1900, though according to the former law leap-years, were made common years, whilst 2000 will be a leap-year. In order to correct a further minute error, namely, the fact that the calendar year as now amended is 26 sec. longer than the true solar year, it is proposed that the year 4000 and all its multiples shall be common years, and not leap years. This is a matter which, though practical, is of distinctly remote importance. Some people like to look well ahead.

The alteration in the calendar made by Pope Gregory was successfully opposed for a long time in Great Britain by popular prejudice. It was called "new style," and was at last accepted, as in other European countries, but has never been adopted in Russia, which retains the "old style." An Act of Parliament was passed in 1751 ordering that the day following September 2nd, 1752, should be accounted the fourteenth of that month. Many people thought that they had been cheated out of eleven days of life, and there were serious riots! The change had been already made in Scotland in the year 1600 without much outcry. The Scotch were either too "canny" or too dull to "fash" themselves about it.

Let us now revert for a moment to the proceedings of Oriental potentates in regard to astronomers, a class of scientific functionaries whom they have from remote ages been in the habit of employing. It appears that in China there is no attempt to make the civil year or year of the calendar coincide with the astronomical year. The astronomical year is reckoned as beginning when the sun enters Capricorn, our winter solstice, and is thus more reasonably defined than is the commencement of our New Year, which is nine days late. Twelve months are recognised; the first is called Tzu, the second Chou, and the third Yin, and the rest respectively Mao, Chen, Su, Wu, Wei, Shen, Yu, Hsu, Hai. But the calendar year, on the other hand, begins just when the Emperor chooses to say it shall. He is like the captain of a ship, who says of the hour, "Make it so," and it is so. With great ceremony he issues a calendar ten months in advance, fixing as he pleases all the important festive and lucky days of the year. Various emperors have made New Year's Day in the fourth, third, second, first, or twelfth month. It has now been fixed for many centuries in the second astronomical month. I have mentioned above that the ancient Greeks reckoned the New Year as beginning about the end of September. But the reckoning differed in the different States, and so did the names of the months. Although the Greek astronomers determined the real solar year with remarkable accuracy, and proposed very clever modes of correcting the calendar so as to use the lunar months in reckoning, there was no general system adopted, no agreement among the "home-ruling" States.