The whole page is taken up with notes on chemistry in relation to colour:
112 lbs of W Lead 24 lb of G Flint. vitrified gives a | yellow color to the lead. Mastick
¼ lb of Soap 2Oz of W Wax one of Arabic or Tragacanth | boil in water
Potash to 2 parts <sulphuric> to mercury acts | upon Iron ? why not copper
Annotto boil in alkaline water becomes | yellow with acids an orange color precipit[...] | color soluable in alkalis which gives it | a deep orange colour. alum the same but dull | Sulphurate of Iron an orange brown | do of Copper brighter yellow Tin lemon Col P
Without establishing their origin, Joyce Townsend suggests the first note is for an ‘industrial-scale recipe for a priming’, with other notes on other processes including the making of ‘annatto, a yellow organic pigment, with different mordants’1 (i.e. fixatives).
This is one of fourteen pages of notes on varnishes and colours resulting from chemical reactions between folio 62 verso (D09974) and folio 55 recto (D09959), working from the back of the sketchbook as now foliated. As discussed in the sketchbook’s Introduction,2 most are taken from William Nicholson’s 1808 Dictionary of Practical and Theoretical Chemistry, beginning here with the unpaginated entry on ‘Pottery’:
The yellow glaze is made by mixing together in water, till it becomes as thick as cream, 112 lb. of white lead, 24 lb. of ground flint, and 6 lb. of ground flint glass. ... The lead is principally instrumental in producing the glaze, as well as in giving it the yellow colour; for lead, of all the substances hitherto known, has the greatest power of promoting the vitrification of the substances with which it is mixed.
It is not clear why the word ‘Mastick’ concludes Turner’s first paragraph, as it does not occur in the adjacent text; Nicholson has a separate entry on ‘Mastic’ (which he spells elsewhere as ‘mastich’), mentioning its use in varnishes. Turner’s notes from ‘Pottery’ continue, taken from a description of varnish used in the manufacture of tobacco pipes: