FEATHERS. (PURIFICATION OF.) The following is an outline of Heal's pro cess : " The feathers are first placed in what is termed a steam-cistern, a chamber of iron, having its floor formed of perforat ed metal, through which a current of steam is made to enter with considerable force, to fill every portion of the cistern, and thoroughly saturate the mass which it contains. This continues for some time, the effect upon the feathers being analogous to that produced upon metallic substances when exposed to the red heat of a furnace. Every particle of animal matter they contain is fused and driven off, being carried away by the steam as it rushes through the mass and escapes by an aperture for the purpose in the roof of the cistern. The feathers, now of course in a damp state, are next placed in a large hollow cylinder of iron, into which by means of a blowing machine, is carried a rapid current of air, heated by a fur nace to a temperature of 300°. This, like the first cylinder, contains a revolving in strument of iron, but having arms or bars of iron ; and these, driven at a great velo city, pass through and through the mass, thoroughly separate it, and keep the fea thers constantly in motion : thus allow ing the current of hot and drying air to permeate them freely, and effectually separating every fibre of them, while through a floor of wire-work passes away a large quantity of dust and refuse, which must be disengaged. Lastly, the feathers
are placed in a hollow cylinder of perfor ated metal, in which revolves a ' fan,' composed of four plates of metal, fixed at equal distances from each other, into a horizontal bar. This is driven with im mense velocity, making about 900 revo lutions in a minute, and carrying round the feathers with it ; the dust, not al ready removed in drying cylinder, is separated by the powerful current of air which is driven through them, and, pass ing the perforations of the cylinder, is =tied away by a drain beneath. By this means the feathers are rendered perfectly sweet, pure, and dry."