very hot season, not less than 1600 gallons were exhaled from one acre in 24 hours. 5. The dew, in its silent, powerful, and beneficial ef fects, affords a lively representation of the influences of the Spirit of God. "I will be as the dew unto Israel, saith the Lord.” No noise like the sound of rain, or the rattling hail, attends the descent of the dew; but in silence, when the eyes of men are closed in sleep, it falls and refreshes the earth :" so the kingdom of God cometh not with observation. Men often affect pomp and display in their works; but Jesus did not cry, nor cause his voice to be heard in the streets." 6. When the times of refreshing from the presence of the Lord were come, he passed by the mighty, and the noble, and commissioned fishermen and tent-makers to publish his gospel, and, by the foolishness of preaching to save them that believe: and still we see the gospel making its progress in a way but little observed by men. 7. A faithful minister delivers his message: the greater part of his hearers, perhaps, pay little or no attention; when, on some unnoticed individual in the assembly, the Spirit descends like the dew on Gideon's fleece, "while all is drought around." None knows how he sorrows after a godly sort: what indignation against sin, what fear of the Divine displeasure, and what velement desire of the Divine favour may agitate his mind! He who is the instrument, in the hand of God, in producing this change, possibly may never hear of his own success: but these influences, though unobserved, are very powerful. 8. It would be as easy to prevent the dew falling on the earth, as to prevent their efficacy! Such a man may be treated as an object of contempt; he may be persecuted as well as despised. The world may take from him his good name, his honour, his wealth, yea, even his life; but no man can take from him that which God hath given, or stop the progress of the work of grace in his heart. He shall be fruitful in the ways of God: "he shall grow as the lily, and cast forth his roots as Lebanon; his branch shall spread, and his beauty shall be as the olive." 9. So beneficial are the influences of the Spirit of God, that he who is the subject of them is a blessing to all around him; and so essential to the spiritual life, that when they are withheld, prayer is a burden, love grows cold, faith becomes feeble, and every grace languishes, like the vegetable productions of the earth when deprived of the refreshing dew. No. XIII. ON LIGHT. LIGHT, in the common acceptation of the term, is that invisible etherial matter which makes objects perceptible to the eye. By some philosophers light is sup posed to be a fluid, present at all times, but which must be put in motion, in order to exeite the sensation of seeing The followers of Sir Isaac Newton, on the contrary, maintain, That it consists of small particles of matter, emitted (or, rather reflected) from the luminous body; and which produce this sensation when they strike the retina. 2. It is however certain, that rays of light consist of particles of matter, for they may be attracted or repelled (a beam of light passing by the edge of a razor will be turned out of its course ;) and that these rays move with such surprising velocity, that a particle of light passes from the sun to the earth (a distance of 90,000,000 of miles) that is, at the rate of 197,916 miles in a second, Yet He who in wisdom hath made all things, hath ordained that the particles of light should be so extremely minute, that, notwithstanding the amazing force which their velocity gives them, they strike the eye without occasioning any degree of pain to that delicate organ. 3. It appears from calculation, that light moves two million times as fast as a ball shot from a cannon; and, consequently, if the particles of light were equal in bulk to the two millionth part of a grain of sand, we should be no more able to endure their impulse than that of sand shot point blank from the mouth of a cannon." This is one amongst a thousand other proofs, that the one great and gracious Creator remembereth our frame, and considereth that we are but dust.' 4. The following well known circumstances prove the astonishing minuteness of the particles of light: A candle may easily be seen in the night at two miles distance, even if viewed through a pin-hole in a card: it therefore follows, that every instant there is emitted light sufficient to fill a circle of four miles in diameter, so as to leave no void space of the size of the fiftieth part of an inch, or a pin's point. Through a hole equally small, by day, may be seen objects which occupy almost an entire hemisphere, as the sky, trees, houses, &c. Rays of light must, therefore, pass through the aperture, at the same instant, from all these objects, and yet there is no confusion, the vision being perfectly distinet. 5. Thus diffusively and rapidly do the rays of light issue from the sun to enliven and revive the face of nature, but far more swift and beneficial thy coming, O my Saviour thou Great Light of the spiritual world! to cherish and support thy suffering saints, agreeable to thy promise: When they call, I will hear; and while they are yet speaking, I will answer.' On the wings of the morning thou fliest to the relief of the contrite spirit; yea, 6 'Compar'd with the speed of thy flight, And the swift winged arrow of light.' No. XIV. THE EYE. THE Eye is in form nearly globular; it consists of three coats and three humours. Fig. 1. represents the section of an eye cut horizontally across the middle. The external coat which is represented by the outer eircle, A B C D, is called the Sclerotica; the front part, BE C, which rather projects, is called the Cornea. The next coat, which is represented by the second circle, is called the Choroides. In the front of this coat is an aperture, a b, through which the rays of light pass into the eye it is called the Pupil. 2. That part of the Choroides which surrounds the pupil, and which in some persons is blue, in others brown or almost black, is called the Iris (see a c be, fig. 2, which represents a front view of the eye.) The Iris may be enlarged or diminished: this is effected by means of two sets of muscular fibres; the one like a number of circles of different sizes placed within each other, so as to have one common centre in the middle of the pupil the other set of fibres appear like lines drawn from that centre to the circumference of the largest circle, and are called Radial Fibres. 3. When too strong a light shines upou the eye, the circular fibres contract and diminish the pupil, by which a less number of rays are admitted. When too little light is received to perceive the object distinctly, the radial fibres contract; by which the pupil is enlarged, and a contrary effect produced. Unless the Iris possessed this property, the most painful effects would be produced, by sudden transitious from a greater to a less degree of light, or the contrary. 4. There are some animals who can so contract the pupil, as to admit a very little light; or enlarge it to such a degree, as to take in the faintest rays, and see objects when other creatures cannot: a wonderful provision for such as seek their prey in the night! 5. The third coat is called the Retina, which spreads like a network all over the inside of the Choroides. Im. mediately under the Cornea is a transparent fluid, like water, and is called the Aqueous Humor; it gives a protuberant figure to the Cornea. At the back of this is situated the Crystalline Humor, d f, in the shape of a double convex glass, of the consistence of a very hard jelly, and perfectly transparent. It is kept in its place by a fine transparent membrane, which attaches it to the circumference of the iris. The rest of the eye, Z Z, is filled with the Vitreous humor, which is t ansparent, and about the consistence of the white of an egA is the Optic Nerve, which proceeds from the eye to the brain. 6. The wisdom and goodness of the Creator appears in the astonishing apparatus of muscles with which the eye is furnished, to produce all the necessary and convenient motions in the situation where it is placed, and in the provision made to preserve this delicate organ from injury. The eyebrows defend the eye from too strong a light; the eyelids act like curtains to cover and protect it during sleep; and, when we are awake, they diffuse a fluid over the eye as often as we wink, which keeps it clean and well adapted for transmitting the rays of light; and lest the sight should be interrupted by this operation, it is performed in an instant; the eye lashes guard the eye from floating dust, with which the atmosphere abounds. 7. It is a remarkable circumstance that fishes, who have no occasion for a defence against dust or motes in the air, have no eyelids. Thus, in the works of Jehovah there is nothing superfluous, and nothing deficient and the more minutely they are examined, the more evidently will it appear that He is excellent in counsel and wonderful in working,' both in the world of nature and of grace! 6 1 No. XV. ON VISION. HAVING described the different parts of the eye, we shall now endeavour to point out their uses in producing |