still superior to the gun. On the 6th of August, at St. Ann's, the 4 ounce and 8-ounce rockets proved superior to the siren. On the Shambles Light-vessel, when a pressure of 13 pounds was employed to sound the siren, the rockets proved greatly superior to that instrument. Proceeding along the sea-margin at Flamborough Head, Mr. Edwards states that at a distance of 114 mile, with the 18-pounder gun hidden behind the cliffs, its report was quite unheard, while the 4-ounce 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 9, 1877, a remarkable series of experiments was 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 minutes after the flash. |
| Melton | 15 | " | Signals distinctly heard. Thought at first that sounds were reverberated from the sea. |
| Framlingham | 18 | " | Signals very distinctly heard, both in the open air and in a closed room. Wind in favor of sound. |
| Stratford. St. Andrews | 19 | " | Reports loud; startled pheasants in a cover close by. |
| Tuddenham. St. Martin | 10 | " | Reports very loud; rolled away like thunder. |
| Christ Church Park | 11 | " | Report arrived a little more than a minute after flash. |
| Nettlested Hall | 6 | " | Distinct in every part of observer's house. Very loud in the open air. |
| Biklestone | 6 | " | Explosion very loud, wind against sound. |
| Nacton | 14 | " | Reports quite distinct mistaken—by inhabitants for claps of thunder. |
| Alboro | 25 | " | Rockets seen through a very hazy atmosphere; a rumbling detonation heard. |
| Capel Mills | 11 | " | Reports heard within and without the observer's house. Wind opposed to sound. |
| Lawford | 1512 | " | Reports distinct: attributed to distant thunder. |
In the great majority of these cases, the direction of the sound inclosed a large angle with the direction of the wind. In some cases, indeed, the two directions were at right angles to each other. It is needless to dwell for a moment on the advantage of a signal commanding ranges such as these.
The explosion of substances in the air, after having been carried to a considerable elevation by rockets, is a familiar performance. In 1873 the Board of Trade actually proposed a light-and-sound rocket as a signal of distress, which proposal was subsequently realized, but in a form too elaborate and expensive for practical use. The idea of the gun-cotton rocket with a view to signaling in fogs is, I believe, wholly due to
