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:
Lastly, the pipes, when baked, should be covered with a glazing or varnish, and afterward rubbed with a cloth. This glazing consists of a quarter of a pound of soap, two ounces of white wax, and one ounce of gum arabic or tragacanth, which are all boiled together in five pints of water for the space of a few minutes.
It appears that the third paragraph, concluded by Turner’s own query, is taken from the nearby entry on ‘Potash’:
It is extremely greedy of oxigen, absorbing it rapidly from the atmosphere, and resuming the alkaline state. If amalgamated with twice its bulk of quicksilver [i.e. mercury], and applied to iron, silver, gold, or platina, these metals are immediately dissolved, and converted into oxides, while the alkali is regenerated.
Turner’s last paragraph is from Nicholson’s entry on ‘Roucou. See Annotto’:
The watery decoction of annotto has a strong smell, and a disagreeable taste. Its colour is of a yellowish red, and it is somewhat turbid. An alkaline solution changes it to an orange yellow, which is brighter and more pleasing ... If we boil annotto in water with an alkali, it dissolves much better than in water alone, and the liquor is of an orange colour.
Acids form with this liquor an orange-coloured precipitate soluble in alkalis, which communicate to it a deep orange colour; the supernatant liquor retains only a pale yellow.
... The solution of alum gives a considerable quantity of orange precipitate, which is deeper than that which acids produce; the liquor remains of a pleasant lemon colour, bordering a little on green.
Sulphat of iron forms a precipitate of an orange brown; the liquor remains of a pale yellow.
Sulphat of copper gives a precipitate of a yellowish brown, somewhat brighter than the former; the liquor preserves a greenish yellow colour.
A solution of tin produces a lemon-coloured precipitate, which is deposited very slowly.
