An essay on calcareous manures / by Edmund Ruffin and edited by J. Carlye Sitterson. Ruffin, Edmund, 1794-1865. Marl. S643 .R92 1842 631.807 RUE Cambridge : Belknap Press of Harvard University Press, c1961. c1961. 1842 Text vii, [13]-316 p. : http://hdl.loc.gov/loc.gdc/scd0001.00027623141 eng John Harvard library Also available in digital form on the Internet Archive Web site. Also available in digital form on the Internet Archive Web site.