No important instrumental modifications have been made since publication of our last list (Yale VII). As before, we are indebted to many collaborators for samples and for assistance with descriptions and comments. Technical assistance has been provided by George Young, Carolyn Haupt, and Jonathan Wood. The generous support of the National Science Foundation, under grants G-19080 (to Stuiver), G-19335 (to Deevey), and G-24049 (to Rouse) is gratefully acknowledged.

It has been shown that contamination from humic acids, chitin, fungal products, etc., contributing young carbon, and from bitumen and carbonate, contributing old carbon, may not be completely removed from wood and char samples by the usual hydrochloric acid and sodium hydroxide pretreatments of the samples. A procedure is offered for the isolation of a pure chemical substance from such samples, cellulose from wood and uncombined carbon from char, that must represent the original material. Cellulose is prepared by boiling the resin-free sample in 1.25% H2SO4 and 1.25% NaOH, adding Schweitzer's reagent, filtering, and precipitating from the filtrate by acidification. Uncombined carbon is separated from char samples as the flocculant precipitate remaining after boiling in 70% HNO3, followed by settling overnight from a large volume of 6M HNO3. A simple procedure for the chemical examination of char samples is also offered for the estimation of the amounts of bitumen, carbonate, combined, and uncombined carbon in char.