The main text of the 'Index' appears on the rectos, with supplementary notes on the facing versos.

An elaborate alphabetical subject-index to the literature of alchemy, giving page references to over 144 different works, with several earlier and less elaborate drafts. In the most finished (though evidently incomplete) version (Ms. 30 a), the references are frequently supplemented by definitions of terms and processes or even short essays on the topic in question.

Ms. 30 a)

f. 1 An unrelated title page and table of contents which appears to have come astray (before the Sotheby sale) from Keynes Ms. 35: many though not all of the headings listed occur also in that manuscript.

f. 2 Title: 'Index Chemicus'. On the following folios (3-94), most head-words are followed by a definition and references, others merely by references, and a few by gaps to be filled in at a later date.

Ms. 30 b)

f. 1r 'Index Chymicus': alphabetical draft list of subject headings for the index, followed (ff. 2-5) by another index, much less developed than that in a) above.

Ms. 30 c)

Another draft 'Index Chemicus' on 12 ff.

Ms. 30 d)

'Supplementum Indicis Chemici' on 8 ff.

Followed by related drafts and supplementary material, also in Latin, c. 5,000 words. Erroneously described in the Sotheby catalogue as 113 pp. + 49 pp.

Detailed account in Westfall, 'Newton's Index Chemicus'; see also his Never at Rest, 358-9.