Abstract This paper contains the results, theoretical and experimental, of work undertaken, at the request of the Ordnance Committee, by the authors as Technical Officers of the Munitions Inventions Department. Permission to publish such parts as appear to be of general scientific interest has now been granted by the Ordnance Committee and the Director of Artillery. The publication of this paper has received their sanction. The experiments in question were carried out at the firing ground of H. M. S. “Excellent,” Portsmouth; the Experimental Department, H. M. S. “Excellent,” also provided the 3-inch guns used and the material for the construction of the range. The authors’ best thanks are due to the officers of this department, especially Lieut.-Commander R. F. P. Maton, O. B. E., R. N., without whose cordial co-operation these experiments could never have been carried out; also to the other officers of the Munitions Inventions Department who assisted in the heavy work of making and analysing the observations. The aeronautical measurements at low velocities, required for comparison, were made in the wind channels of the National Physical Laboratory, by arrangement with the Director and the Superintendent of the Aero­nautical Department, to whom also we wish to express our thanks.