SINGEING OF WEBS

The old furnace for singeing cotton goods is represented in longitudinal section, fig. 1030. , and in a transverse one in fig. 1031. a is the fire-door; b , the grate; c , the ash-pit; d , a flue, 6 inches broad, and 2 1 ⁄ 2 high, over which a hollow semi-cylindrical ma of cast iron e , is laid, one inch thick at the sides, and 2 1 ⁄ 2 thick at the top curvature. The flame pa es along the fire-flue d , into a side opening f , in the chimney. The goods are swept swiftly over this ignited piece of iron, with considerable friction, by means of a wooden roller, and a swing frame for raising them at any moment out of contact. In some shops, semi-cylinders of copper, three quarters of an inch thick, have been substituted for those of iron, in singeing goods prior to bleaching them. The former last three months, and do 1500 pieces with one ton of coal; while the latter, which are an inch and a half thick, wear out in a week, and do no more than from 500 to 600 pieces with the same weight of fuel. In the early part of the year 1818, Mr. Samuel Hall enrolled the specification of a patent for removing the downy fibres of the cotton thread from the interstices of bobbin-net lace, or muslins, which he effected by singeing the lace with the flame of a gas-burner. The second patent granted to Mr. Hall, in April, 1823, is for an improvement in the above proce ; viz., causing a strong current of air to draw the flame of the gas through the interstices of the lace, as it pa es over the burner, by means of an aperture in a tube placed immediately above the row of gas-jets, which tube communicates with an air-pump or exhauster. IMG:4147767755307473660_illo1139b.png:Singeing apparatus Fig. 1032. shows the construction of the apparatus complete, and manner in which it operates; a , a , is a gas-pipe, supplied by an ordinary gasometer; from this pipe, several small ones extend upwards to the long burner b , b . This burner is a horizontal tube, perforated with many small holes on the upper side, through which, as jets, the gas pa es; and when it is ignited, the bobbin-net lace, or other material intended to be singed, is extended and drawn rapidly over the flame, by means of rollers, which are not shown in the figure. The simple burning of the gas, even with a draught chimney, as in the former specification, is found not to be at all times efficacious; the patentee, therefore, now introduces a hollow tube c , c , with a slit or opening, immediately over the row of burners; and this tube, by means of the pipes d , d , d , communicates with the pipe e , e , e , which leads to the exhausting apparatus. This exhausting apparatus consists of two tanks, f and g , nearly filled with water, and two inverted boxes or ve els, h and i , which are suspended by rods to the vibrating beam k ; each of the boxes is furnished with a valve opening upwards; l , l , are pipes extending from the horizontal part of the pipe e , up into the boxes or ve els h and i , which pipes have valves at their tops, also opening upward. When the ve el h descends, the water in the tank forces out the air contained within the ve el at the valve m ; but when that ve el rises again, the valve m being closed, the air is drawn from the pipe e , through the pipe l . The same takes place in the ve el i , from which the air in its descent is expelled through the valve n , and, in its ascent, draws the air through the pipe l , from the pipe e . By these means, a partial exhaustion is effected in the pipe e , e , and the tube c , c ; to supply which, the air rushes with considerable force through the long opening of the tube c , c , and carries with it the flame of the gas-burners. The bobbin-net lace, or other goods, being now drawn over the flame between the burner b , b , and the exhausted tube c , c , by means of rollers, as above said, the flame of the gas is forced through the interstices of the fabric, and all the fine filaments and loose fibres of the thread are burnt off, without damaging the substance of the goods. To adjust the draught from the gas-burners, there are stopcocks introduced into several of the pipes d ; and to regulate the action of the exhausting apparatus, an air ve el o , is suspended by a cord or chain pa ing over pulleys, and balanced by a weight p . There is also a scraper introduced into the tube c , which is made, by any convenient contrivance, to revolve and slide backwards and forwards, for the purpose of removing any light matter that may arise from the goods singed, and which would otherwise obstruct the air pa age. Two of these draught tubes c , may be adapted and united to the exhausting apparatus, when a double row of burners is employed, and the inclination of the flame may be directed upwards, downwards, or sideways, according to the position of the slit in the draft tube, by which means any description of goods may, if required, be singed on both sides at one operation. The greater part of the bobbin-net lace made in England, is sent to Mr. Hall’s works, at Basford, near Nottingham, to be singed; and at a reduction of price truly wonderful. He receives now only one farthing for what he originally was paid one shilling. SKIN ( Peau , Fr.; Haut , Germ.); the external membrane of animal bodies, consists of three layers: 1. the epidermis, scarf-skin, ( Oberhaut , Germ.); 2. the vascular organ, or papillary body, which performs the secretions; and 3. the true skin, ( Lederhaut , Germ.), of which leather is made. The skin proper, or dermoid substance, is a ti ue of innumerable very delicate fibres, cro ing each other in every po ible direction, with small orifices between them, which are larger on its internal than on its external surface. The conical channels thus produced, are not straight, but oblique, and filled with cellular membrane; they receive ve els and nerves which pa out through the skin ( cutis vera ), and are distributed upon the secretory organ. The fibrous texture of the skin is composed of the same animal matter as the serous membranes, the cartilages, and the cellular ti ue; the whole po e ing the property of di olving in boiling water, and being, thereby, converted into glue. See Glue , Leather , and Tan . SLAG ( Laitier , Fr.; Schlacke , Germ.); is the vitreous ma which covers the fused metals in the smelting-hearths. In the iron-works it is commonly called cinder . Slags consist, in general, of bi-silicates of lime and magnesia, along with the oxides of iron and other metals; being analogous in composition, and having the same crystalline form as the mineral, pyroxene . See Copper and Iron . SLATES ( Ardoises , Fr.: Schiefern , Germ.) The substances belonging to this cla may be distributed into the following species :— 1. Mica-slate, occasionally used for covering houses. 2. Clay-slate, the proper roofing-slate. 3. Whet-slate. 4. Polishing-slate. 5. Drawing-slate, or black chalk. 6. Adhesive slate. 7. Bituminous shale. 8. Slate-clay. 1. Mica-slate. —This is a mountain rock of vast continuity and extent, of a schistose texture, composed of the minerals mica and quartz, the mica being generally predominant. 2. Clay-slate. —This substance is closely connected with mica; so that uninterrupted transitions may be found between these two rocks in many mountain chains. It is a simple schistose ma , of a bluish-gray or grayish-black colour, of various shades, and a shining, somewhat pearly internal lustre on the faces, but of a dead colour in the cro fracture. Clay-slate is extensively distributed in Great Britain. It skirts the Highlands of Scotland, from Lochlomond by Call ender, Comrie, and Dunkeld; resting on, and gradually pa ing into mica-slate throughout the whole of that territory. Roofing-slate occurs, on the western side of England, in the counties of Cornwall and Devon; in various parts of North Wales and Angle sea; in the north-east parts of Yorkshire, near Ingleton, and in Swale dale; as also in the counties of Cumber land and West mor land. It is likewise met with in the county of Wicklow and other mountainous districts of Ireland. All the best beds of roofing-slate improve in quality as they lie deeper under the surface; near to which, indeed, they have little value. A good roofing-slate should split readily into thin even lam inæ; it should not be absorbent of water either on its face or endwise, a property evinced by its not increasing perceptibly in weight after immersion in water; and it should be sound, compact, and not apt to disintegrate in the air. The slate raised at Eisdale, on the west coast of Argylls hire, is very durable.