11. Intercalary months.
In order to reconcile the lunar and solar years the Hindus hit upon an ingenious device. It was ordained that any month in which the sun did not enter a new sign of the zodiac would not count and would be followed by another month of the same name. Thus in the month of Chait the sun must enter the sign Mesha or Aries. If he does not enter it during the lunar month there will be an intercalary Chait, followed by the proper month of the same name during which the sun will enter Mesha.[9] Such an intercalary month is called Adhika. An intercalary month, obtained by having two successive lunar months of the same name, occurs approximately once in three years, and by this means the reckoning by twelve lunar months is adjusted to the solar year. On the other hand, the sun very occasionally passes two Sankrānts or enters into two fresh signs during the lunar month. This is rendered possible by the fact that the time occupied by the sun in passing through different signs of the zodiac varies to some extent. It is said that the zodiac was divided into twelve equal signs of 30° each or 1° for each day, as at this period it was considered that the year was 360 days.[10] Possibly in adjusting the signs to 365 odd days some alterations may have been made in their length, or errors discovered. At any rate, whatever may be the reason, the length of the sun’s periods in the signs, or of the solar months, varies from 31 days 14 hours to 29 days 8 hours. Three of the months are less than the lunar month, and hence it is possible that two Sankrānts or passages of the sun into a fresh sign may occasionally occur in the same lunar month. When this happens, following the same rule as before, the month to which the second Sankrānt properly belongs, that is the one following that in which two Sankrānts occur, is called a Kshaya or eliminated month and is omitted from the calendar. Intercalary months occur generally in the 3rd, 5th, 8th, 11th, 14th, 16th and 18th years of a cycle of nineteen years, or seven times in nineteen years. It is found that in each successive cycle only one or two months are changed, so that the same month remains intercalary for several cycles of nineteen years and then gives way generally to one of the months preceding and rarely to the following month. Suppressed months occur at intervals varying from 19 to 141 years, and in a year when a suppressed month occurs there must always be one intercalary month and not infrequently there are two.[11]
This method of adjusting the solar and lunar years, though clumsy, is so far scientific that the solar and lunar years are made to agree without any artificial intercalation of days. It has, however, the great disadvantages of the frequent intercalary month, and also of the fact that the lunar months begin on different dates in the English solar calendar, varying by nearly twenty days.
12. Superstitions about numbers.
It seems not improbable that the unlucky character of the number thirteen may have arisen from its being the number of the intercalary month. Though the special superstition against sitting down thirteen to a meal is, no doubt, associated particularly with the Last Supper, the number is generally unlucky as a date and in other connections. And this is not only the case in Europe, but the Hindus, Persians and Pārsis also consider thirteen an unlucky number; and the Muhammadans account for a similar superstition by saying that Muhammad was ill for the first thirteen days of the month Safar. Twelve, as being the number of the months in the lunar and solar years, is an auspicious number; thirteen would be one extra, and as being the intercalary month would be here this year and missing next year. Hence it might be supposed that one of thirteen persons met together would be gone at their next meeting like the month. Similarly, the auspicious character of the number seven may be due to its being the total of the sun, moon and five planets, and of the days of the week named after them. And the number three may have been invested with mystic significance as representing the sun, moon and earth. In the Hindu Trinity Vishnu and Siva are the sun and moon, and Brahma, who created the earth, and has since remained quiescent, may have been the personified representative of the earth itself.
13. The Hindu months.
The names of the Hindu months were selected from among those of the nakshatras, every second or third being taken and the most important constellations apparently chosen. The following statement shows the current names for the months, the nakshatras from which they are derived, and the constellations they represent:
| Month. | Nakshatra. | Constellation. | |||
| 1. | Chait. | Chitra. | Virgo. | ||
| 2. | Baisākh. | Visacha. | Libra. | ||
| 3. | Jeth. | Jyestha. | Scorpio. | ||
| 4. | Asārh. |  | Pūrva Ashādha. |  | Sagittarius. |
| Uttara Ashādha. | |||||
| 5. | Shrāwan. | Sravana. | Aquila. | ||
| 6. | Bhādon. | | Pūrva (E) Bhadrapada. | | Pegasus. |
| Uttara (N) Bhadrapada. | |||||
| 7. | Kunwār or Aswīn. | Aswini. | Aries. | ||
| 8. | Kārtik. | Krittika. | Pleiades (Part of Taurus). | ||
| 9. | Aghan or Mārgashīr. | Mrigasiras. | Orion. | ||
| 10. | Pūs. | Pushya. | Cancer. | ||
| 11. | Māgh. | Magha. | Leo. | ||
| 12. | Phāgun. | | Pūrva (E) Phālguni. | | Leo. |
| Uttara (N) Phālguni. |