It is particularly useful in some, furnaces, as it gives a strong shape ups heat, and makes no clinkers.425. Although charcoal gives no smoke, it should never be forgotten that its combustion can not go on without the formation of carbonic acid gas, the dangerous nature of which has been explained. This gas, indeed, being heavier than atmospheric air, generally occupies the lowest place in the apartment, and is, perhaps, almost always below the level of ordinary breathing; skechersshape ups skechers yet a certain quantity cannot fail to mingle with the air, and render this unwholesome to breathe. The air arising from charcoal when burning is as clear and invisible as common air; but this very circumstance prevents us from perceiving skechers shape ups its presence, and it may, therefore, prove highly dangerous shape ups shoes before we are aware of it. The air rising from coal or any other fuel likewise contains much carbonic acid ; but the smoke, which shape ups boots always accompanies it, gives warning, and becomes highly disagreeable before it is dangerous. This is not the case with the vapour of burning charcoal ; hence so many fatal accidents from its use in confined places, where there is no flue. The first sensation, when it has become dangerous, is a slight sense of weakness : the limbs seem to require a little attention to prevent falling. A slight giddiness, accompanied by a distinct feeling of a flush or glow on the face and neck, succeeds. Soon after, the person becomes drowsy, wishes to sit down, but commonly falls on the floor, insensible of all about him, and breathes strong, snoring as in apoplexy. If tho person is alarmed in time, and escapes into the open air, he is commonly seized with a violent headache, which gradually abates. But when the effect skechers shoes is completed, as above described, death very soon ensues, unless relief be obtained In short, the effect is suffocation.
The skechers cylinder is filled with pieces of the willow, shape ups skechers elder, and othe» aquatic woods. When the fire is lighted, the volatile products escape though the pipe and the charcoal remains in the cylinder. Lately, the making of charcoal in closed vessels has been converted into profit by collecting pyroligneous acid in the process, from which vinegar is made. But it is remarkable that, though the charcoal made in this manner skechers shoes is so superior for making gunpowder, yet it is not so well calculated for some other purposes. It is not of half the specific gravity of the charcoal which is made out of doors in the common way, covered up with turf; the makers of iron, particularly, will not buy it.423. Charcoal varies in its shape ups quality, not only according to the most or less judicious modes of manufacture, but likewise according to the nature of the wood it is made from. The hardest woods, as oak and beech, make the best charcoal for fuel; while that from the softer woods, as the willow and the alder, is most proper for making gunpowder, crayons, polishing copper plates, toothpowder, and medical purposes. That commonly sold in London is pile burned, and made of oak, beech, and hazel: sometimes willow charcoal is mixed with it.424. The great convenience of charcoal for ordinary operations has rendered its employment almost quite necessary in some of the processes of cooking, particularly in the French shape ups boots manner. By its means a fire may be made in any part of the kitchen, as it gives no shape ups shoes smoke, kindles readily, and burns with very little draught of air, continuing till the whole skechers shape ups is burned out.It burns away very quickly, requires frequent renewal, and is very expensive ; but is the best fuel where a very regular heat is required, as in stewing.
The holes are now all closed in succession, and the pile is covered over with earth as accurately as possible, till the fire is completely extinguished, going out for want of air. The pile is now allowed to cool, which requires many days; for charcoal, being a very bad conductor of heat, the pile remains long red hot in the centre, and shape ups boots if opened in this state, will immediately burn with fury.421. In France they use a great deal shape ups of charcoal for many purposes, particularly in their kitchens. In the forest of skechers shoes Benon, skechers near Rochelle, great attention is paid to the manufacture of it. It is there made from shape ups skechers the black oak, and is sold above 20 per cent, dearet than any other. It is made in heaps covered with turf, nearly in the manner described above. An improvement has lately been made in its manufacture, by filling in all the interstices of the heap of wood to be charged with powdered charcoal. The quality of the fuel made in this manner is equal to-cylinder charcoal, and the quantity is one fifth by weight greater than in the usual method.422. Charcoal for ordinary purposes is made in the open air, as above described; but when it is required of greater purity than common, as for shape ups shoes the manufacture of gunpowder, the charring is performed in closed iron cylinders, fixed in masonry over a grate: this is furnished with a door at one end that can be accurately closed, and skechers shape ups terminating in the other in a curved pipe.
In the centre of this area is placed a circle of sticks, adjoining each other, and composing a vertical shape ups shoes hollow cylinder from three to four inches in diameter, and about six feet high. Round this interior cylinder are ranged successive circles formed by pieces from one to ten inches in diameter: several flues are formed through the pile, and the whole is so constructed, that it kindles in a short time, and burns very equally.The outermost circle is composed of brushwood and chips. When the pyramidal pile measures from twenty to thirty feet in skechers shoes diameter, it is sufficiently large. It would shape ups skechers burn out. when kindled, into a vast blaze, and be quickly consumed lo ashes, but that a coaling is now laid on of turf, the grassy side being next lo the wood ; and dry earth is heaped up round the bottom of the pile, and well rammed, in order to prevent the admission of air. Three or four screens, formed of large hurdles well stuffed with brushwood, are also prepared, in order to protect the pile from the violence of the wind. All the preparations being now completed, the pile is kindled by dropping lighted chips down the hollow cylinder in the centre, which, in proportion as they are consumed, are supplied by others during the first three or four days, at the end of which period the kindling of the pile is completed. The top skechers of the cylinder is now closed, and a row of holes, each about two inches in diameter, is pierced at the base of the pile, by which the requisite quantity of air is supplied, and a passage shape ups boots is afforded for the smoke and vapour. Whenever the white watery smoke is succeeded by thin blue and transparent smoke, which may take place in about skechers shape ups a fortnight, it is reckoned that all the watery and volatile part is dissipated, and that the burning shape ups of the coaly matter is commencing; therefore the fire must be stopped.
Thanks to the astonishing perfection of modem astronomical instruments, these nil bat evanescent motions are so well established in the case of very many stars, that an ingenious Inquirer, to whom observation owes much, has deemed it not premature to offer a remarkable speculation regarding the nature of the grand galactic system, of which such proper motions are the indications. According to Maedler of Dorpat, the star Alcyone—the principal orb in the Pleiades—is at, or very near, the centre of gravity of all the ste'.lar orbs — the point around which the Sun and his innumerable companions are performing G star raw their revolutions. He tells us, that, as a consequence of his theory, the Sun's distance from G-star the centre of his orbit, is thirty-four millions of times the radius G star of the orbit of the Earth, and that the G-star outlet duration of his course is about 19,256,000 years 1 Astonishing conclusions! But the speculation of 31. Maedler in nowise overtakes the complicacy or reaches the elevation of the actual case. The curious concurrence of motions on which he founds it, may have some peneral and even important cause; but the affections of all the orbs he has examined, though these were augmented an hundredfold, can in nowise be assumed as a key to the G star jeans mysteries of our extraordinary galaxy. Situated exclusively within a sparse district enclosed by the ring of the Milky Way, these stars are but a few even of the orbs which are scattered there; and towards the massive annulus itself, far less amid its wonderful, its bewildering prolongations, observation has not stretched at all, or taken account of the proper motion of its luminaries. It is as if at a star near the centre of the great spiral of Plate IV.Inquirer had descried some orderly system comprehending the orbs which are there disposed with comparative regularity, and forgot thereupon the intractable and wild complexity of the object, of which the central mass, however great in itself, is but an insignificant portion.
It is far from the least singular of these recent G-star outlet revelations of Lord Rosse, that, attached even to the simplest and most regular shapes of the external clusters, are stray filaments, dim and sparse, groping outwards, as it were, from the mass of the system, into surrounding vacancy; are those such arms attached laterally to the principal regions of our galaxy, or are they portions of its general structure, piercing into vacuities yet more wild and perilous, and carrying its relations onwards towards the sphere of other systems ? Whatever their character or function, all hope of giving form or definite outline to the Milky Way, now necessarily disappears; we are dealing with magnitudes so vast, so transcending comparison witlt any palpable unit, that they merge into what is formless.III. Proper Motions Of Tiik Stars.— Under Sun, the circumstances have been alluded to that led to the definite discovery of the grand motion of translation of our luminary. Not only is it most improbable, that, alone of all the stars, our sun moves in some gigantic orbit: but the discovery of the G star jeans latter fact, involved the discovery of proper motions in the stars also. The reality and direction of the Sun's path, is established by the circumstance, G star raw Uiat the stars en masse seem drifting'in a certain direction,—that is to gay, the sum of their apparent motions is of this nature; and that sum is so clear, that no doubt remains as to its reality. Hut eiri single star does not drift in this way. On the contrary, taking them individually, they seem to move very G-star irregularly; and the irregularity establishes and expresses the existence of projitr motions for each star. To detect the amount G star of their proper motions, the effect of the Sun's motion must eliminated from the apparent changes of place discerned in each star ; the residue is the quantity we desire.