146 



KIDD'S OWN JOUENAL. 



time observed in the flash and in the report 

 of her guns. 



It is another proof of the difference of 

 wind and sound, that sound travels very 

 nearly as quick against the wind as with it, 

 though a contrary wind diminishes, and a 

 fair wind increases, its loudness. That 

 sounds of different tones travel with the 

 same velocity, is evident from what we 

 observe on listening to a peal of bells, or to 

 any instrument of music ; for all the tones 

 come in succession to our ears ; whereas, if 

 they did not travel at the same rate, they 

 would be heard confusedly jarring with one 

 another. The lowest whisper accordingly, 

 travels as rapidly as the loudest thunder. 



It is also to be remarked, that sounds 

 proceed with the same velocity through a 

 long or a short space — a large or a small 

 distance. Sounds also travel with the same 

 velocity by night and by day ; in damp and 

 in dry weather. This, however, is not to be 

 understood as having the same effect on 

 their loudness and lowness. Like the rays 

 of light, sound is supposed to proceed in 

 straight lines ; though from its being greatly 

 more reflexible than light, it can pass 

 through the winding tube of a French horn, 

 which light cannot do. Not only so, but 

 the intensity of sound is much increased in 

 the passage through a winding tube — a 

 principle on which the speaking-trumpet is 

 constructed. 



Like the rays of light also, sound can be 

 reflected from certain bodies ; and when this 

 takes place, it is called an echo, a word 

 derived from the Greek. By taking advan- 

 tage of the principle, echoes have been 

 formed by art, as mirrors have been made 

 for reflecting light. It was once thought 

 that concave bodies were indispensable to 

 produce echoes. A single flat wall, how- 

 ever, will produce an echo ; and Le Cat says 

 he has even observed that some convex 

 bodies reflected sound, though a vault, or a 

 bending wall, is the best form. 



A third property, in which sound re- 

 sembles light, is its power of penetrating 

 and passing through hard substances. Light 

 passes through glass and diamonds ; and 

 sound in a similar manner passes through 

 iron and other metals, as well as through 

 wood. It may be also remarked, that other 

 circumstances being the same, the harder or 

 more dense the substance, sound pene- 

 trates it the more easily, and in this respect 

 it bears a strong resemblance to heat. 



When the ear is placed close to one end 

 of a log of wood, however long it may be, 

 and the other end is struck, or a watch 

 applied to it — we are sensible of the sound of 

 the watch or of the stroke, though it be too 

 slight to be otherwise perceptible. When a 

 piece of metal is applied to the bones of the 



head, or to the teeth, and struck, we also 

 feel an indistinct sensation of sound, and 

 this is felt even by those who are deaf to 

 sounds conveyed through the air. 



We purpose a further consideration of this 

 subject in two more chapters. There are 

 some remarkable phenomena attendant upon 

 sound, to which we are anxious to direct 

 particular attention. 



BIRDS OF SONG. 



tfo. XXV.— THE BLACK-CAP. 



It is A fact admitted by all careful 

 observers, that the black-cap, like the night- 

 ingale, regularly revisits, year after year, 

 the scenes of his childhood. Where he was 

 born, there lies his heart. This cannot be 

 a matter for wonder or surprise ; indeed, ap- 

 preciating their instinct as we do, it would 

 be strange were it otherwise. 



This very year, we recognised most readily, 

 by the peculiarity of his voice and richness 

 of his notes, one of our favorites that left us 

 last autumn. There is so much difference in 

 the quality of their song, and also in the 

 arrangement of their notes, that you might 

 really " swear" to a particular bird. We speak 

 of this identical bird, because of his rare 

 excellence. Doubtless many others, of 

 second-rate powers, accompanied him to 

 their old quarters. Nature is always true to 

 herself. 



The black-cap is known to naturalists as 

 the contralto singer of the woodland choir. 

 His fine, varied, musically joyous voice, 

 arrests the attention of the most listless tra- 

 veller, and he feels his weary way beguiled 

 by such an attendant. Main describes the 

 strain of the black-cap as occupying about 

 three bars of triple time in the performance ; 

 and he very justly adds, that although very 

 frequently repeated, it is varied at every 

 repetition. He begins with two or three 

 short essays of double notes, gradual crescendo 

 up to a loud and full swell of varied expres- 

 sion. One passage in particular often occurs, 

 as truly enunciated as if it were performed 

 on an octave flute. It has been remarked, 

 that the style and key of the song are nearly 

 the same in all the tribe ; but all have no& 

 the power of improvising such extraordinary 

 " variations." This is Nature's own gift 



In some situations, this bird courts unusual 

 retirement, and you can very rarely get a 

 sight of him. When this is the case, approach 

 carefully to the spot where you hear him 

 singing, and conceal yourself under the near- 

 est bushes. While you remain quiet, he will 

 unsuspectingly continue his song ; and even 

 should you by chance disturb him, he will, 

 if you stand still, speedily recommence 

 singing. These birds are of so joyous a 



