Correspondence and plans for new telescopes, new inventions and improved techniques. There are numerous plans for a new transit circle at Greenwich and arrangements for the zenith sector; a drawing of W. Lassell's polishing machine; J. Locke's paper on his electro-chronograph; O.M. Mitchel's new method of observing transits; the Earl of Rosse's reflecting telescope; a plan for an equatorial telescope; trials of Barlow's Telescope by W.H. Smyth; clock trials; a double image micrometer; and W.H. Miller's water clock for equatorial telescopes, with drawings. The correspondents include R. Sheepshanks, J.F.W. Herschel, W. Whewell, D.F.J. Arago, H.A.E.A. Fayé and the Earl of Rosse. There is also is a table for division of the old quadrant and sliding rules for the error of collimation.