780 HAIR 



HJEMOGXiOBXir. The red -col curing matter of the blood. See BLOOD. 



H AIDING-ERITE. A hydrated arsenato of lime, named after the late VonHai- 

 dinger, of Vienna. 



HAIR (Cheveu, Grin, Fr. ; Ifaar, Ger.) is of all animal products the one least 

 liable to spontaneous change. It can be dissolved in water only at a temperature 

 somewhat above 230 F., in a Papin's digester ; but it appears to be partially decom- 

 posed by this heat, since some sulphuretted hydrogen is disengaged. By dry distilla- 

 tion, hair gives off sulphuretted gases, while the residuum contains sulphate of lime, 

 common salt, much silica, with some oxide of iron and manganese. It is a remarkable 

 fact that fair hair affords magnesia, instead of these latter two oxides. Horse-hair 

 yields about 1 2 per cent.' of phosphate of lime. 



We have no recent analysis of hair. Vauquelin found nine different substances in 

 black hair ; in red hair, a red oil instead of a greenish black one. 



Hairs are tubular, their cavities being filled with a fat oil, having the same colour 

 with themselves. Hair plunged in chlorine gas is immediately decomposed and con- 

 verted into a viscid mass ; but when immersed weak in aqueous chlorine, it undergoes 

 no change, except a little bleaching. 



Living hairs are rendered black by applying to them for a short time a paste made 

 by mixing litharge, slaked lime, and bicarbonate of potash, in various proportions, 

 according to the shade of colour desired. The ordinary mode of dyeing human hair is 

 first to saturate the hair with the sulphide of potassium in solution ; then, when this 

 has been well absorbed and is partially dry, a solution of nitrate of silver is to be ap- 

 plied. By varying the proportions of the sulphide, and the strength of the silver solu- 

 tion, almost any tone of colour, from a brown to a black, can be produced. 



The salts of silver, mercury, lead, bismuth, as well as their oxides, blacken hair, 

 or make it of a dark violet, by the formation, most probably, of metallic sulphurets 

 (sulphides). 



Hair as an object of manufacture is of two kinds, the curly and the straight. The 

 former, which is short, is spun into a cord, and boiled in this state, to give it the 

 tortuous springy form. The hairs of rabbits and hares are prepared for the hatmaker 

 by a process called secretape, so as to render them fit for felting. The skins with the 

 hair still upon them are laid upon a table, and with a brush, made from the bristle of 

 the wild boar, a solution of nitrate of mercury is applied many times in succession, till 

 every part of the fur be equally touched, and till about two-thirds of the length of the 

 hairs be moistened. The skins are then placed together to complete the impregnation, 

 and put into a store-room. In drying there is a retraction of the hairs, and the re- 

 quired curling is produced. The long straight hair is woven into cloth for sieves, and 

 also for ornamental purposes, as in the damask hair-cloth of chair-bottoms. For this 

 purpose the hair may be dyed in the following way : 



Forty pounds of tail hair, about 26 inches long, are steeped in lime-water during 

 twelve hours. Then a bath is made with a decoction of 20 Ibs. of logwood, kept 

 boiling for three hours, after which time the fire is withdrawn from the boiler, and 

 10 ounces of copperas are introduced, stirred about, and the hair is immersed, having 

 been washed from the lime in river-water. The hair should remain in this cooling 

 bath for twenty-four hours, when the operation will be finished. Hair used for weav- 

 ing is obtained principally from South America and from Russia. All the black and 

 grey hair is dyed for the manufacture of black hair-cloth for covering furniture. 

 White only can be dyed so as to produce what are called fancy colours, and great care 

 is required in the process. 



The quality of hair-cloth, as well as the brilliancy and permanency of the colours, 

 depend in a great degree on the nature of the warp, which may be either of cotton, 

 linen, or worsted. Coloured hair-cloth is made at Worcester, Sheffield, and Paris, and 

 used for covering sofas and chairs, and for railway carriages. 



The looms for weaving hair differ from the common ones, only in the templet and 



the shuttle. Two templets of iron must bo 

 used to keep the stuff equably but lightly 

 stretched. These templets, of which one 

 is represented in fig. 1 126, are constructed in 

 the shape of flat pincers ; ihe jaws, cc, being 

 furnished with teeth inside. A screw, D, 

 binds the jaws together, and hinders the 

 M'lvnp! from jroing inwards. Upon the side 

 cross-beam of the loom, seen in section at 

 i, a bolt is fixed which carries a nut P 

 at its end, into which a screwed iron rod E enters, on one of whose ends is the handle 

 B. The other extremity of the screw K is adapted by a washer and pin to the back of. 

 the pincers at the point H, so that by turning the handle to the right or the left, we 



