Sir Isaac Newton has asserted, according to Nicholson, (British Encyclopedia) "that the density of the sun's heat, which is proportioned to his light, is seven times as great in Mercury as with us, and that water there would be all carried off in the shape of steam, for, he found, by experiments with the thermometer, that a heat seven times greater than that of the sun's beams in summer will serve to make water boil." That fixed stars are of the same nature as the sun, since they agree with it in several particulars, as in the property of emitting light continually, and in retaining constantly their relative situation with but little variation, is generally admitted. They are supposed also to emit heat as well as light. The sun is, therefore, considered a fixed star comparatively near us, and the fixed stars, which seem as centres to other systems of worlds, as suns at immense distances from us. Taking the distance of the sun from us to be, as is found by calculation, 95,000,000 miles, we may infer, that every thing must be scorched up at its surface; but this question is put at rest, if we consider that the sun's rays act on a calorific medium, as the cause of changing quiescent into distributable heat. May not light itself, by some process unknown to us, produce calorific rays? That heat and light are both material, and possess some properties in common, that for instance, of reflection and refraction, are facts well known; but to account for the peculiar agency of light, if it be admitted, is a problem, which, perhaps, will never be settled?
[4] Fire must have been a very potent instrument in the hands of Hannibal, if we believe what Livy and Pliny assert respecting the means he employed in crossing the Alps, which took him fifteen days, after meeting with almost every obstacle. Livy tells us, that Hannibal softened the rock by pouring vinegar upon it, after it had first been made hot under flaming piles of huge trees! M. Rollin quotes Pliny to prove that vinegar has the force to break stones and rocks! This story is altogether fabulous; for in the first place, had he vinegar sufficient; and, secondly, who ever knew that vinegar had force, or even the power of dissolving primitive rocks, such as granite or gneiss; and, thirdly, if it possessed the power stated by Pliny, and had he a sufficient quantity, where was his wood? For Polybius assures us, that Hannibal had no wood to make a fire with, and that there was not a tree in the place, where he then was, nor near it. That Hannibal passed over the Alps into Italy, and at an inclement season of the year, is certain, and that it was one of the greatest achievements that an enterprising commander ever accomplished, is generally admitted.
[5] Respiration is a mechanical and chemical process, and consists in alternate inhalation and exhalation, which, in consequence of the oxygen gas in the air, effects a change in the venous blood that enters the lungs from the pulmonary artery. Now as this blood is charged with carbon, to which its dark purple colour is owing, it is carried off in union with oxygen in the form of carbonic acid. Hence carbonic acid is produced in respiration and the venous blood is changed into the bright red arterial blood. A common sized man will consume about 46 thousand cubic inches of oxygen per diem; equivalent to 125 cubic feet of air, and makes about twenty respirations in a minute, or for every seven pulsations breathes twice.
[6] Of this fact the reader may form some idea, when he is informed, that Newton's Principia, Biot's Physique, Hatchette, Gregory, &c. &c. form the class books of instruction, works which require deep study, and profound thought.
[7] Various applications of chemistry, among which that to gunpowder, drew my attention at an early period of life. In the Aurora of Philad. I published a series of essays on this and other subjects, which, from the letters received at that time, I flatter myself tended in some degree to advance the manufacturing interest in the United States; an interest, which is connected with our individual and national prosperity, and the permanent and practical independence of the republic. These essays were entitled "Application of chemistry to the arts and manufactures," and published in 1808. I have since enlarged that plan in the Artist's Manual, &c. 2 vols. 8vo. While noticing this subject we may add, that, having the honour of being one of the few of the original society of Philadelphia for the promotion of National Industry, whose essays excited, as they claimed, the attention of the citizens of the United States, much is due to the indefatigable labours of some of the members of that association. We are greatly indebted to the able and masterly pen of Samuel Jackson M. D. Professor of Pharmacy in the college of Apothecaries, of Philadelphia, for many of the best essays it produced, whose disinterested motives, liberal and exalted mind, and pure patriotic feeling prompted him to the laudable undertaking; and whose essays were full, clear, and comprehensive. Viewing his talents, his worth, his merit, we may truly add, that he is not only an honour to the country which gave him birth, but an ornament to the age in which he lives. The able address of the Philadelphia Linnæan society, penned and signed by him, the late Samuel Benezet M. D., and the author, as a committee, although written many years ago, contains the principles, which are now advocated for the support and encouragement of national industry. This address was calculated, however, to promote, at the same time, the interests of Natural History.
[8] Incombustible cloth made of this substance was formerly in use, not only for domestic purposes, but, also to retain the ashes of the dead from those of the funeral pile. Cloth made of amianthus, when greased, or soiled, may be cleansed by throwing it into a bright fire. It is then restored to a dazzling white colour. Pliny, the naturalist, saw table cloths, towels, and napkins of amianthus taken from the table of a great feast, thrown into the fire, and burnt before the whole company; and by this operation, he says, they became better cleansed than if they had been washed.
Pontoppidan (Natural History of Norway) remarks, that he has a piece of paper made of the Norway asbestus, which, when thrown into a fierce fire, is not in the least wasted, but what is written on it totally disappears. In Norway, the stone flax is prepared by beating it in water, till the fibres separate, which are repeatedly washed, and then dried in a sieve. It is afterwards spun, observing to moisten the fingers with oil.
[9] In the year 1601, a horse, which had been taught to perform a number of tricks, was tried, as possessed by the devil, and condemned to be burnt. Joblonski affirms in his Lexicon, &c. that he was condemned to the flames in Lisbon. Nothing was a greater imposition on mankind than the Oracles. The imposition of causing statues to speak, as the head of Orpheus in the island of Lesbos, the Æsculapius of Alexander, &c. may be readily perceived, when Lucius relates, that, in the case of Alexander's oracle, he took instead of a pipe, the gullet of a crane, and transmitted the voice through it to the mouth of the statue! Bishop Theophilus, in the fourth century, broke to pieces the statues at Alexandria. He found some which were hollow, and placed in such a manner against a wall, that a priest could slip unperceived behind them, and speak to the ignorant populace through their mouths. Professor Beckman observes, "that the Pagan priests, like our jugglers, were afraid that their deceptions, if long practised, might be discovered. They considered it, therefore, as more secure to deliver the answers themselves, or cause them to be delivered by women instructed for that purpose, or by writings, or by any other means. We read, nevertheless, that idols, and the images of saints once spoke; for at present the latter will not venture to open their mouths. If their votaries ever really heard a voice proceed from the statue, it may have been produced in the before-mentioned manner." We think, that a contrivance, similar to the bull of Phalaris, in the place of hollow statues, would furnish a good reality.
The oracle of Apollo at Delphos, says Percy, having been consulted about the manner of stopping a plague then raging at Athens, returned for answer, that the plague should cease, when Apollo's altar, which was cubical, should be doubled. The philosophers of Athens immediately applied themselves to discover the duplicature of the cube, which henceforward was called the Delian Problem, and continued for a long time to be an object of the keenest pursuit to the curious. The first who discovered the solution was Hippocrates Chias.
[10] Signs in the heavens were believed by the ancients; and even with regard to natural occurrences, they produced melancholy and awful reflections. Augustus Cæsar was so afraid of thunder and lightning, that, though he carried about him a skin of a sea-calf, which was in those days accounted an excellent paratonnerre, yet, whenever he saw a tempest coming, he used to fly for refuge to some vaulted place underground. Caius Caligula rivalled Augustus in this respect; for Suetonius observes, that when it thundered, he would wrap his head in some covering; or, if in bed, leap out of bed and hide himself under it.