An Explanation of the Terms “Adihmâsa,” “Ûna-Râtra,” and the “Aharganas,” as Representing Different Sums of Days

The months of the Hindus are lunar, their years solar; therefore their new year’s day must in each solar year fall by so much earlier as the lunar year is shorter than the solar (roughly speaking, by eleven days). If this precession makes up one complete month, they act in the same way as the Jews, who make the year a leap year of thirteen months by reckoning the month Adar twice, and in a similar way to the heathen Arabs, who in a so-called annus procrastinationis postponed the new year’s day, thereby extending the preceding year to the duration of thirteen months.

On the leap month.