These are the principal comparative trials made between the gun-cotton rocket and other fog-signals; but they are not the only ones. On the 2nd of August, 1877, for example, experiments were made at Lundy Island with the following results. At 2 miles distant from the firing-point, with land intervening, the 18-pounder, firing a 3-lb. charge, was quite unheard. Both the 4-oz. rocket and the 8-oz. rocket, however, reached an elevation which commanded the acoustic shadow, and yielded loud reports. When both were in view the rockets were still superior to the gun. On the 6th of August, at St. Ann's, the 4-oz. and 8-oz. rockets proved superior to the syren. On the Shambles Light-vessel, when a pressure of 13 lbs. was employed to sound the syren, the rockets proved greatly superior to that instrument. Proceeding along the sea margin at Flamboro' Head, Mr. Edwards states that at a distance of 1.25 mile, with the 18-pounder previously used as a fog-signal hidden behind the cliffs, its report was quite unheard, while the 4-oz. rocket, rising to an elevation which brought it clearly into view, yielded a powerful sound in the face of an opposing wind. On the evening of February 9th, 1877, a remarkable series of experiments were made by Mr. Prentice at Stowmarket with the gun-cotton rocket. From the report with which he has kindly furnished me I extract the following particulars. The first column in the annexed statement contains the name of the place of observation, the second its distance from the firing-point, and the third the result observed: Stoke Hill, Ipswich 10 miles Rockets clearly seen and sounds distinctly heard 53 seconds after the flash. Melton 15 miles Signals distinctly heard. Thought at first that sounds were reverberated from the sea. Framlingham 18 miles Signals very distinctly heard, both in the open air and in a closed room. Wind in favour of sound. Stratford. 19 miles St. Andrews Reports loud; startled pheasants in a cover close by. Tuddenham. 10 miles St. Martin Reports very loud; rolled away like thunder. Christ Church Park. 11 miles Report arrived a little more than a minute after flash. Nettlestead Hall 6 miles Distinct in every part of observer's house. Very loud in the open air. Bildestone 6 miles Explosion very loud, wind against sound. Nacton 14 miles Reports quite distinct--mistaken by inhabitants for claps of thunder. Aldboro' 25 miles Rockets seen through a very hazy atmosphere; a rumbling detonation heard.