Copy of letter from George Abercromby, Brucefield to Robert Arbuthnot, dated 22 January 1784. The letter is about improved methods of salt manufacture. This item was enclosed with Coll-16/II/158-159.

Draft letter from Joseph Black to Robert Arbuthnot, dated 14 February 1783. The letter is about Mrs. Gordon's vinegar and was written in reply to Coll-16/II/89.

Draft reply from Joseph Black to Robert Arbuthnott, secretary to the Board of Trustees for Fisheries, Manufactures and Improvements in Scotland, in favour of George Cottrel's blast furnace.

Letter from Robert Arbuthnot, Trustees Office, Edinburgh to Joseph Black, dated 28 January 1783. The letter is about Mrs. Gordon's process for making vinegar.

Letter from Robert Arbuthnot, Trustees Office, Edinburgh to Joseph Black, dated 16 February 1784. The letter is about ashes for alkali and enclosed a letter from George Abercromby to Arbuthnot (Coll-16/II/157F, now in outsize sequence).

Letter from Robert Arbuthnott, secretary to the Board of Trustees for Fisheries, Manufactures and Improvements in Scotland, to Joseph Black and James Hutton asking their opinions on George Cottrel's blast furnace.