Correspondence with tradesmen, including letters from booksellers; coal merchants; clock repairers; horologists; builders; chandlers; merchants; machine repairers; instrument makers; stationers; parcel carriers; engineers; chemists; decorators; journeymen; import agents; picture framers; fitters; plaster manufacturers; a photographer; telegraph companies; the Kent Water Company; the Gutta Percha Company; and the South Eastern Railway. The letters cover various instructions; requests; accounts; invoices; bills; receipts; tenders; circulars; routine repairers; and various adjustments and improvements to instruments. There are letters from O. Struve, F.A.T. Winnecke, E.J. Stone, J. Glaisher and C.V. Walker; plans and proposals for the transit circle instruments; and plans for rebuilding the magnetical observatory.