Letters and papers concerning new inventions; trials of improved instruments, especially the transit circle, Great Equatorial and altazimuth instruments; and improved techniques. The correspondents include B.A. Gould, C. Pritchard, E. Dunkin, E.J. Stone, L. Respighi, O. Struve, W.H.M. Christie, W. De La Rue, J.C. Maxwell, W. Huggins, S.J. Perry, A.V. Auwers, M.C. de Littrow, C.J.E. Wolf, A. Laussedat and J.R. Hind. There is a description and plans of the Great Equatorial Telescope; description and engraving of Cooper's achromatic telescope; articles on W. De La Rue's observatory from 'The Engineer', with four photographs; pieces on the Workmen's International Exhibition, 1870; C.A. Young's paper on a printing chronograph; M.C. de Littrow's paper on finding longitude; J.C. Naish's Tellurian Globe in 'The Illustrated London News'; auction catalogues; and a lecture on longitude by W. Ellis in 'The Horological Journal'.