The Rattle
The tail of the rattle snake is provided with several joints, formed of a bony substance, and put together in a loose manner, so that when shaken they produce a rattling sound. Whether the design of nature in giving the snake this instrument is to enable it to warn other animals and men of the danger of coming too near, or for some other purpose, we can only conjecture.
There is a mystery, too, in respect to its venom. Some have supposed that this venom was given to it as a means of killing its prey before devouring it. Other serpents are endowed with the power of killing their prey by the prodigious force which they can exercise in coiling round the limbs of the animal they have seized, breaking its bones in the terrible gripe which they give it, and thus putting a sudden and total stop to all the vital operations. All serpents seem to require some extraordinary means of killing their prey, for they are formed to live upon animals much larger than themselves, and which they could not kill by any ordinary means.
There is a considerable number of species of serpents with rattling tails in America, but it is singular that there are none of any kind in the old world. The whole tribe of rattlesnakes is an American production altogether.
The Rattlesnake more Sinned Against Than Sinning
Notwithstanding the hatred with which the rattlesnake is regarded and the opprobrium which is cast upon him by man, he seems, after all, to be more sinned against than sinning, for he really is a very quiet and peaceable beast, that has no quarrel with man, and never injures him unless he honestly supposes that he is called to do it in self-defense. If he sees a man coming toward him, he crawls quietly away, if a way of retreat is open to him, If not, and if his enemy still approaches with an aggressive air, he feels himself justified in defending himself by the only means with which nature has provided him. He winds himself up into a spiral coil, with his head projecting from the center of it, and as soon as his enemy comes near, he darts forward and upward, and strikes his fang into his enemy's flesh, at a point as high from the ground as he can attain.
He Acts Always on the Defensive
He, however, seldom or never attacks man of his own accord, but warns him away by sounding his rattle when he sees him coming inadvertently near. It results from this his peaceable disposition that, though the prairies in the western country, and the forests at the south, are full of rattlesnakes, numbering probably millions upon millions, and the slaves upon the plantations, and the farmers and emigrants and railway laborers in the woods, are continually encountering them, it is very rare that lives are lost from their venom. How great must be the forbearance, we might almost say the generosity exercised by the reptile, to lead to such a result as this!
This generosity, however, if generosity it be, seems to be very little appreciated by man. Man everywhere attacks and kills every rattlesnake that he sees. He strikes him on the neck with a club if he wishes to kill him at a blow; and if, on the other hand, which is more frequently the case, he wishes to tease and torment him for a while before putting him to death, or if he wishes to capture him, he comes with a forked stick, and sets the prongs of it into the ground, one on each side of the poor victim's neck. He then grasps his neck behind the stick with his hand and takes him up with impunity. It is even possible, while holding him thus, to extract his fang, or the little bag of poison at the root of it, and thus render him entirely harmless.
The Humming Bird
From the rattlesnake, one of the most repulsive of all animals to man, we turn with pleasure to the humming bird, an animal that likewise owes a part of his celebrity to a sound that he makes, though the instrument with which he makes it is a pair of wings instead of a tail. Whatever of mystery there may be about the rattling made by the reptile, there is none in respect to the humming noise made by the bird. The sound is due simply to the rapidity of the vibrations of the wings, and this is due to the smallness of the bird. For the smaller the bird and the smaller the wings, the more rapid must be the motion of them to sustain the weight of the body in the air.
Vibrations Producing Sound
Sound is produced by the vibration of any substance in contact with the air, by which vibrations are imparted to the air, and thus transmitted to the ear. If the vibrations are slow no audible sound is produced. Thus the motion of the pendulum of a clock, the wagging of the tail of a dog, the motion of the hand up and down in the air, as rapid as it is possible to make such a motion, produce no sound.
As we increase the rapidity of such vibrations, however, we at last come to a limit where a sound begins to be heard. This is about thirty-two beats in a second. The humming bird's wings, therefore, must move to and fro more than thirty-two beats in a second, and it is simply in consequence of the fact that his body and wings are so small that the rapidity of the motion of his wings comes within the limit above referred to, and sound is produced. The wings of a swallow make less than thirty-two pulsations in a second, and thus that bird moves through the air silently.
As the rapidity of the vibrations of any moving body increases the sound becomes higher in pitch. Thus the wings of a mosquito, moving much more rapidly than those of a humming bird, made a more acute sound. As the rapidity increase still more, we reach at last a point where sound is no longer produced. This limit varies with different ears, but with most persons it is at about eight thousand vibrations a second that sound ceases to be heard. This upper limit, however, is extremely vague.
The number of vibrations corresponding with the middle c of a musical instrument, according to the diapason recently established by the French government, if five hundred and twenty-two. That of a sound one octave below is half as great; of one an octave above is twice as great. Thus by finding the pitch of the sound made by the wings of a humming bird, by means of a piano forte or other instrument, the number of vibrations made by them in a second can be approximately ascertained.
The Humming Bird's Mode of Life
The humming bird is designed, like the bee, to feed on the sweet juices found in flowers. But being a bird, and thus, small as he is, too large and heavy to alight upon the flower and rest his weight upon it, he is provided with wings to poise himself in the air, and a long slender bill to serve as a pipe with which to draw out the juices from the innermost recesses of the largest corollas.
There are a great many different species of humming birds, all peculiar to America. None are found in any part of the old world. There is a difference in the form, and also in the plumage of the different species. In some of them the feathers, especially those of the neck and breast, are splendidly iridescent, glowing with all the colors of the richest gems. Nothing can exceed the beautiful effect of these colors when the bird is seen poised in the sun before the flower from which he is extracting the juices with his long and slender bill. At such a time his wings cannot be seen, so swift is their motion; or if a glimpse of them is obtained, they produce only the effect of a little quivering mist at his sides. He seems like a wingless bird poised motionless in mid air.
If at such a time anything occurs to alarm him or to attract his attention, he darts off through the air a little way, quick as a flash, then suddenly stopping and poising himself upon his wings, he rests as motionless as if he were standing upon the ground. Then, after contemplating for a moment the object that alarmed him, he shoots off again through the air, with a motion so quick that the eye can scarcely follow him - and is gone.