Correspondence on new techniques and instruments, including a clock for the uniform movement of a barrel, a new transit circle at Greenwich, observations with one altazimuth instrument, notes on the reflex zenith telescope, object glasses, determining longitude by telegraph by G.P. Bond, O.M. Mitchel's galvanic method of observing declination, and Eble's instrument for determining time and experiments with mercury. The correspondents include C. Pritchard, the Earl of Rosse, H.A.E.A. Fayé and various instrument makers. There are catalogues of instruments, a piece in 'The Civil Engineer and Architects Journal' on astronomical instruments at the Great Exhibition, an engraving of T. Cooke's equatorial telescope, and an advertisement for Miss Readhouse's lunar globes.