The solar day, the solar year, and the lunar month, or **lunation**, may therefore be called the natural divisions of time.

Though the /see' are thus strictly portions of solar time, yet what is remarkable, though not peculiar to China, they give their name to the lunar months, each month or **lunation** having the name of the chung-ki or sign at which the sun arrives during that month.

As the /see' is longer than a synodic revolution of the moon, the sun cannot arrive twice at a chung-ki during the same **lunation**; and as there are only twelve tsee, the year can contain only twelve months having different names.

It must happen sometimes that in the course of a **lunation** the sun enters into no new sign; in this case the month is intercalary, and is called by the same name as the preceding month.

As It Had Now Been Discovered That The Exact Length Of The **Lunation** Is A Little More Than Twenty Nine And A Half Days, It Became Necessary To Abandon The Alternate Succession Of Full And Deficient Months; And, In Order To Preserve A More Accurate Correspondence Between The Civil Month And The **Lunation**, Meton Divided The Cycle Into 125 Full Months Of Thirty Days, And 110 Deficient Months Of Twenty Nine Days Each.

If The Last **Lunation** Of Any Year Ends, For Example, On The 2Nd Of December, The New Moon Falls On The 3Rd; And The Moon'S Age On The 31St, Or At The End Of The Year, Is Twenty Nine Days.

Now That **Lunation** Having Commenced On The 3Rd Of December, And Consisting Of Thirty Days, Will End On The 1St Of January.

Hence, If In That Year The Epact Should Be 19, A New Moon Would Fall On The 2Nd Of December, And The **Lunation** Would Terminate On The 30Th, So That The Next New Moon Would Arrive On The 3 Ist.

But the fourteenth of this moon falls at the latest on the 18th of April, or 29 days after the 20th of March; for by reason of the double epact that occurs at the 4th and 5th of April, this **lunation** has only 29 days.

The Calendar Is Constructed On The Assumptions That The Mean **Lunation** Is 29 Days 12 Hours 44 Min.

The Mean Length Of The Year Is Therefore 3541) Days, Or 354 Days 8 Hours 48 Min., Which Divided By 12 Gives 293 G O Days, Or 29 Days 12 Hours 44 Min., As The Time Of A Mean **Lunation**, And This Differs From The Astronomical Mean **Lunation** By Only 2.8 Seconds.

**LUNATION**, the period of return of the moon (luna) to the same position relative to the sun; for example, from full moon to full moon.