In conformity with the foregoing item of law, 7 in the Summer and Fall of the year 1841, the brethern entered into measures to build a baptismal font in the cellar floor near the east end of the temple. President Joseph approved and accepted a draft for the font, made by Brother William Weeks; and on the 18th day of August of that year, Elder Weeks began to labor on the construction of the font with his own hands. He labored six days and then committed the work to carpenters.
[Fillerup, Robert C., compiler; William Clayton Nauvoo Diaries and Personal Writings, A chronological compilation of the personal writings of William Clayton while he was a resident of Nauvoo, Illinois. http://www.boap.org/LDS/Early-Saints/clayton-diaries]