The Rishis, measuring time, have given particular names to particular portions. Five and ten winks of the eye make what is called a Kashtha: Thirty Kashthas make what is called a Kala. Thirty Kalas, with the tenth part of a Kala, make a Muhurta. Thirty Muhurtas make up one day and night. Thirty days and nights form a month, and twelve months form a year. Persons well-read in mathematical science say that a year is made up of two solar motions. viz., the northern and the southern.
काष्ठा निमेषा दश पञ्च चैव त्रिंशत्तु काष्ठा गणयेत् कलां ताम्। त्रिंशत्कलश्चापि भवेन्मुहूर्ता भागः कलाया दशमश्च यः स्यात्॥ त्रिंशन्मुहूर्तं तु भवेदहश्च रात्रिश्च संख्या मुनिभिः प्रणीता। मासः स्मृतो रात्र्यहनी च त्रिंशत् संवत्सरो द्वादशमास उक्तः॥ संवत्सरं द्वे त्वयने वदन्ति संख्याविदो दक्षिणमुत्तरं च॥