পাতা:পদার্থবিদ্যাসার.djvu/৭৭

66 Pup. Whence does the moisture proceed that keeps the eye clean 2 . Tut. To keep the eye moist and clean, which is necessary to its use, a wash is formed by a certain secretion that is perpetually going on, and the superfluous brine is conveyed to the nose through a persorahou in the bone. When once it has entered the nose, it spreads itself upon the inside of the nostril, and is evaporated by the current of warm air, which is continually passing over it. - IPup. Is mot ihe ear also curiousiy formeri? • Tut. It is a most wonderful construction, indeed; but for a knowledge of this, too, you must wait till you are a little older. It is now sufficient for you to know, that the ear is made of a gristiy substance, to sland asnost stift, to caich the sout.d, and to conduct it within the auditory tube. Pup. What is the cause of our being able to understand each other instantaneously Tut. That we may have an immediate perception of each other's words, God has given to sound a swiftness twice as great as that of a ball that issues from the mouth of a cannou. . . Pup. Astonishing indeed; but you have not mentioned the sense of smelling. * Tut. Our wise Creator has placed this sense in a part projecting above the mouth; that we may perceive what is pure and good by its own fragrance ; and discover what is unsound and unwholesome be fore it enters the mouth. The nostrils, wisely adapted to this end, are broad below to receive the smell. Through these also pass the sharp humours of the head; and when during the time of our eating, we othreathe with the mouth, we can breathe through the nostrils. -