much more simple and economical. The Chinese have been form of a flattened cone, .and the rubber being properly vul-the cylinder is a cover made of a wire frame communicating long acquainted with the circulation of the blood; they in-canized, the tooth becomes firmly attached to the dental with the pipe which admits the pure water, When, there oculated for small pox in the tenth century; and about the piece. The hole being obtained by placing on the rear side fore, the whole mass is in

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... , the rags, after passlllg sante time they invented pI·inting. Their bronze money was of the mold of the tooth, which is molded of materials well through the knives of the cylinder and plate are carried up made as early as 1,100 B. C " and its form has not been changed known to tooth manufacturers, the base of a piece of weod, an inclined plane in the trough and the foul water is carried since the beginning of the Christian era, The mariner's or of any other suitable material, cut into the shape of a off througIt the waste pipe below; in this way the rags are compass, gunpowder, and the art of printing were made cone, and which can be consumed or melted at a lesser degree cut bruised, and washed. known to Europe through stories told by missionaries return-of heat than that required for the baking of the tooth; this After the above opBl'l1tion is continued for a sufficient time, ing from Asia. These missionaries, coasting the shores of piece of wood or other material being destroyed during the the water is let off and the cleansed mass is removeu to a the CelCiil tial Empire in Chinese junks, saw a little box con-process of biscuiting, there remains in the center of the tooth press for tIle purpose of driving out the greater part of the taining a magnetized needle, ca.1led Ting·nan·Tchen, or a hollow, corresponding in size and silapo with the material water. They then undergo the process of "neelllewhich points to the south," They also noticed terrible which has been burnt out. The principle of strength which BLEACHING. machines usell by the armies in China, called Ho-pao, or fire-is claimed for this tooth consists in the fact, that the rubber, This process reduces all descriptions of rags to a uniform guns, into which was put an inflammable powder, which a portion of the dental piece to which it is to be attached, whiteness, and requires to be so conducted as not to inj urc the produced a noise like thunder, and projected stones and entering into the tooth itself, the tooth actually forms part quality of the fabric. On being l'emoved from the press the pieces of iron with irresistible force. and parcel, so to speak, of the dental piece; and the principle rags are placed in a receiver, or chamber made of wood, from The first aspect of China produces that impression on the of the invention consists in the holloW in the center of the which the external air is carefully excluded. Into this cham· mind which we call the grotesque. This is merely because tooth of a larger size than the orifice by which the rubber, bel' are conveyed pipes comml'lnicating with a retort, in w1lich the customs of thhs singular nation are so opposite to our own. or other plastic material is introduced, of whatever form this a chemical chlorine is formed by the application of heat to :1 They seem morally, no less than physically our antipodes, hollow may be, whether produced by the consumin g' , melting, due proportion of manganese, common salt, and sulphuric Setting Mineral Teeth. of knives at given distancos apart, projecting a little more bor is in a great measure superseded by machinery. In papor Surgeon Duchesne, of Paris, has invented a method of iix-:,han an inch from its axis; and beneath the roller is a plate in making, machinery is not only a saving 01 manual labor, but ing mineral teeth to the dental piece. Each tooth is furnishell which is also attached a number of knives. When the cylineconomizes time and money, and largely m UltiplifR tho faciJi with a hollow of a size exceeding that of the orifice, by del' commences its revolutions, of which it is made to make ties for its manufacture, as will be made plainly manifest to which orifice the rubber in its plastic state enters into the about 160 per minute, the rags aro carried with great rapidity the most indifferent observer. tooth, assuming inside the internal con figuration, and, as it through the knives; and as the cylinder is depressed or ele- The 1)rocess of converting a thin pulp into puper by ma· Were, the shape of a nail-head of a pyramidal form, or of the vated, the rags are bruised or cut as may be required. Above chinery is a rapid though complicated opemtiliJll. In the © 1869 SCIENTIFIC AMERICAN, INC. SEPTEMmm 18, 1869.] whole range of labor-saving machinery there is perhaps no series of contrivances which 60 forcibly address themselves to the senses; and yet, with all its intricate and wonderful oper ations, there is nothing mysterious in it, as the spectator can see and comprehend its workings from the beginning to the end. At one extremity of the machine is a large chest which is kept full of pulp, and through which a wooden cylinder with fan-shaped projections attached, is kept revolving to keep the fibers of rags, which resemble pure snow flakes, perpetu ally moving, and consequently equally suspended in the the water which contains them. At the bottom oi the chest is a cock through which a continuous stream of pulp flows into a vat placed below it, which is always kept filled to a certain hight. This pulp flows through a narrow wire sieve, situated in the upper part of the vat, and is also kept in mo tion to make the sifting process the more complete. Having passed through the sieve the pulp flows through a pipe in the vat still onward to a ledge, over which it falls in a regular stream, like a sheet of water over a smooth dam; here it is caught upon a plane which presents an uninter rupted surface of five or six feet, upon which it is evenly spread. This plane is constanly moving onwards with a grad ual pace, and has also a shaking motion from side te side. This plane is composed of an endless web of the finest w�e very closely woven together. The pulp does not flow over the sides of the plane because of a strap on each side, which is kept moving and passing upon its edges, and which regu lates the width of the paper. After passing the wheels where these straps terminate, the paper is sufficiently formed not to require any further boundary to define its size. The pulp at this stage has ceased to be a fluid though the paper is �till tender and wet. When it quits the plane of wire the paper passes over a large cylinder covered with felt, upon another plane also "overed with felt, which moves onward the same as the wire plane. This felt surface is also endless, being united at the extremities like a towel upon rollers. It now travels up an inclined plane of felt, which gradually absorbs its moisture, when it is seized between two rollers which pow erfully squeeze it. From thence it travels up another plane of felt and through a second pair of pressing rollers. The paper up to this point is quite formed but it is fragile and still damp; from these i't is received upon a small roller, and is guided by this over the polished surface of a large heated cylinder. The soft tissue now begins to smoke and the pa per commences to harden. From this cylinder or drum,. it is received upon a second, considerably larger and much hotter than the first; as it rolls over the polished ilurface of the drum all the roughness of its appearance when in the cloth region gradually vanishes. At length having passed over a third cylinder, still hotter than the second, and having been subjected to the pressure of a blanket which confines it on one side, while th� cylinder smoothes it on the other, it is caught upon the last cylinder, which passes it over to the reel, upon which it is wound in a finished state but in an end less roll. It has now to be cut into required lengths so as to form the size of the sheet. This is done in a supplementary machine which receives it oft of the reel, and by means of a circular knife it is cut into the requisite lengths. The paper is counted into quires and reams, folded double, and subjected to a certain pressure, so that it may pack close for marketable purposes. From the commencement of the process, when the pulp first flows into the wire web until the paper into which it is formed is received upon the reel, a little less than two minutes is occupied. The web of wire travels at a rate which produces twenty-five superficial feet of paper per minute. In a machine the thickness of the paper is regulated by the quantity of stuff which is allowed to flow out of the chest; and all that is required to render the thickness in variable is an invariable speed in the motion of the machine. If thp web of wire travels at a rate that will form twenty-five feet of pa per per minute, and the chest discharges five gallons of pulp in the same period, there can be no change in the thickness of the sheet; but let the machine move at greater speed, say at the rate of twenty-five per minute, while the discharges are uut five gallons, and the paper will be thinner by one fifth. Again, let j,he pace of the wire plane be unaltered, and the chest discharge ten instead of five gallons per minute, and the sheet will be just double the thickness. In conclusion it should be remarked that the process of con verting rags into pulp is the same with machine-made as with hand-made paper, except that in the former it is con ducted on a more extensive scale. A hundred years ago rags were made into pulp, first by washing them by hand and then by plaeinlfthem in close vessels until they became half rotten, and afi,er the fiber was nearly destroyed they were re d.ced to pulp either by hammering in a mortar or by a cylin der grinding against the sides of a cirCl!!l ar wooden bowl. These operations were slow, expensive, and very destructive to material; and yet, crude as the method was, it existed for centuries, and so continued up to the period when science stepped in to enlighten mankind with its manifold wonders., 179 fired vertical class, cylindricILI in the external casing, as well -was too much for his nervous system, so that when we were as in the internal fir,e-box, and domed on the top, while the present he was unable to perform. The exhibitor kindly gave flames from the fire-box pass off to the chimney through a us a good deal of information about his collection which was single central uptake tube, which formed a most important very interesting. The fle-as are generally imported from Rus tie between the crown of the fire-box and that of the external sia and Belgium as being larger and more docile than the casing. BoUers of this type are very simple in construe-English ones, and are set to work immediately, the training tion, and well calculated when new to resist a high pressure, beginning with a starvation of two days. At first they are so that they art) very generally adopted. The dimensions of very refractory, persisting'in progressing by a series of violent the one under consideration were: Height, 8 ft. 9 in.; diam-jumps instead of a proper jog trot; but after a week or so eter, 3 ft. 6 in. in the external shell, and 2 ft. 9 in, in the fire-they sober down and draw their burdens steadily unless box; while the thickness of the plates was l�r.-th in., and the stirred up to violent exertion, when they will gallop vigor load on the safety-valve, per square inch, '10 lb. The defect ously for a few inches, but sit down to rest and regain their to which it is now wished to call attention, was a deep groove breath directly afterwards. After they once learn to walk or furrow running' entirely round the inner casing of the steadily, we are told, it is difficult to persuade them to leap fire-box at the bottom of the water space, and eating into the again. At night all the performers are unharnessed and fed metal to a depth varying from t to -fRoth in., so that more on the back of the employer's hdnd, after which repast they than'half the strength of the plate was gone. This is not a repose in a box enveloped in cotton wool. If at night any peculiar case; others very similar havd been met with, and' performer does not feed heartily, and with a good appetite, supply of sugar, and that Louisiana will not for five, and, perhaps, ten years, produce as much sugar as she did before the war. So that the producer of sorghum. may calculate upon a good substantial and a continuous profit from the busines/i!, and also lipon the chances amounting almost to a certainty that the profits will be for some years, at least, ex traordinary. Under these circumstances the" revival of in terest in sorghum," must, we think, become a permanent and a growing revival. Portable Boilers .