274 FKAGMENTS OF SCIENCE. 



Bildestone . . . 6 " Explosion very loud, wind 

 against sound. 



Nacton 14 " Reports quite distinct mis- 

 taken by inhabitants for 

 claps of thunder. 



Aldboro' . . . . 25 " Rockets seen through a very 

 ha/y atmosphere; a rum- 

 bling detonation heard. 



Capel Mills . . . 11 " Reports heard within and with- 

 out the observer's house. 

 Wind opposed to sound. 



Lawford .... 15| " Reports distinct : attributed to 

 distant thunder. 



In the great majority of these cases, the direction 

 of the sound enclosed 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 possessing 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, moreover, the Board 

 of Trade 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 a gun-cotton rocket fit for signalling 

 in fogs is, I believe, wholly due to Sir Richard Collin- 

 son, the Deputy Master of the Trinity House. Thanks 

 to the skilful aid given by the authorities of Wool- 

 wich, by Mr. Prentice, and Mr. Brock, that idea is now 

 an accomplished fact; a signal of great power, handi- 

 ness, and economy, being thus placed at the service of 

 our mariners. Not only may the rocket be applied in 

 association with lighthouses and lightships, but in the 

 Navy also it may be turned to important account. 

 Soon after the loss of the ' Vanguard ' I ventured to 

 urge upon an eminent naval officer the desirability 



