180 AKNXAL OF SCIENTIFIC DISCOVERT. 



blast of air under tlio same circumstances. He found, if the plate 

 was tliifk in proportion to tiio diamt'ter of the orifiee, no tone 

 couKi l>u iu'anl. With small orifices in thin plates, air would 

 produce no sound, while water Howinij throusjh the same oriliee 

 produced a <listinet note. Another dilVereiiee In'tween the musi- 

 cal capaliililies of air and water was, that, l)y increased pressure, 

 ah* woulil produce' several successive harmonic tones, while with 

 water the (|uality only of the tone ehanire<l. He found, as Savart 

 had jireviously, that the soinid dep( nded on the tiil)e as well as 

 the oriliee. Soiiillian>s lielieves that a nnisieal soimd can be 

 produced hy hlliui;; the mouth with water, and stjuirtinjj^ it out 

 throuj^'h a small opening between tin? lips; but he coukl not as- 

 certain if any one liad ever suci-essfiiliy ])r;ietiei'd this <lesiral)le 

 accomplishment, lie stales, in comUision, liiat, I'rom the readi- 

 uess with which sounds are produced by licpiids, there is great 

 proli:d»ilily that the depths of the sea are n(»t the silent aboiles 

 whieii Wf usually suppose-. Tlie fish, iiy squirting out or sucking 

 in water through orilices in tiieir mouths or in their opercula, 

 might readily produce great varieties of tones. The genera 

 C'ottus and Trigla, which are known to jiroduce st)unds, are 

 prol)al>ly Ity no means tiie oidy vocal lisii ; and, in fact, the saying, 

 " Mute as a lish,'" shouhl be iliscarded from the company of uu- 

 impeachably true proverbs. — Reader. 



FOG-SIGNAL. 



A novel fog-signal has recently been erected on the island of 

 Ushant, near Brest, lor the jnu-pose of warning sailors of the 

 proximity of the land ihuing foggy weather. The a])paratus 

 consists of a large trumpet lixed vertically on a reservoir of com- 

 pressed air, sui)plied by a blowing engine worked by two horses. 

 The bell of the trumpet is bent at riglit angles, and can be moved 

 horizontally through an angle of 1HU°, so as to throw the sound 

 in any direction. Communication may be made with the reser- 

 voir l)y means of a stop-cock, so that a continuous or intermittent 

 sound may be jirodnced at pU-asure. The sound is so iKnverful 

 that it may be heard at a distance of three or four nautical miles. 

 It is stated that the authorities intend placing these trumpets on 

 several of the most dangerous jfjarts of the French coast. 



NATURE OF SOUND. 



At the meeting of the National Academy of Sciences, in 1866, 

 Prof. Henry gave an interesting paper on some recent experi- 

 ments with fog-bells. The board of officers, wiiich has charge of 

 the lighthouse system, consists of six persons, three of whom are 

 members of this academy. Before the war, they met once a 

 month ; but for the last live years they had met everj- Saturday, 

 to consider various questions of management. They had recently 

 been trying fog-signals at New Haven. A steam-gong, which 

 consisted of two whistles, from fourteen to twenty inches in 

 length, and one foot across, set mouth to mouth, blown by a 



