Correspondence concerning the Greenwich transit circle; adjustments to the altazimuth instrument and photoheliograph, with corrections; O. Struve on the proposed Russian refractor; and various suggestions sent to Airy. The correspondents include J.H. Dallmeyer, A.A. Common, W. De La Rue and W.H.M. Christie. There are papers by E. Plantamour and M. Loewy, in French, on spirit levels and flexure of the telescope; J. Hampden on sun dials; and E.T. Loseby on the benefits of spun glass. There are also two photographs of Jupiter, one showing four satellites, and a coloured drawing of part of a chronograph.