532 PENS, STEEL 



have been thus baked, the crucible is to be removed from the fire, and allowed to cool 

 with the pencils in it. 



Should the pencils be intended for drawing architectural plans, or for very fine lines, 

 they must be immersed in melted wax or suet, nearly boiling hot, before they are put 

 into the cedar cases. This immersion is best done by heating the pencils first upon 

 a gridiron, and then plunging them into the melted wax or tallow. They acquire by 

 this means a certain degree of softness, are less apt to be abraded by use, and preserve 

 their points much better. 



When these pencils are intended to draw ornamental subjects with much shading, 

 they should not be dipped as above. 



Second Process for making Artificial Pencils, somewhat differing from the preceding. 

 All the operations are the same, except that some lamp-black is introduced along with 

 the plumbago-powder and the clay. In calcining these pencils in the crucible, the 

 contact of air must be carefully excluded, to prevent the lamp-black from being 

 burned away on the surface. An indefinite variety of pencils, of every possible black 

 tint, may thus be produced, admirably adapted to draw from nature. 



Another ingenious form of mould is the following : 



Models of the pencil-pieces must be made in iron, and stuck upright upon an iron 

 tray, having edges raised as high as the intended length of the pencils. A metallic 

 alloy is made of tin, lead, bismuth, and antimony, which melts at a moderate heat. 

 This is poured into the sheet-iron tray, and, after it is cooled and concreted, it is in- 

 verted, and shaken off from the model bar, so as to form a mass of metal perforated 

 throughout with tubular cavities, corresponding to the intended pencil-pieces. The 

 paste is introduced by pressure into these cavities, and set aside to dry slowly. When 

 nearly dry, the pieces get so much shrunk that they may readily be turned out of the 

 mould upon a cloth table. They are then to be completely desiccated in the shade, 

 afterwards in a stove-room, next in the oven, and lastly ignited in the crucible, \vith 

 the precautions above described. 



M. Conte recommended the hardest pencils of the architect to be made of lead melted 

 with some antimony and a little quicksilver. 



In their further researches iipon this subject, M. Cont6 and M. Humblot found 

 that the different degrees of hardness of crayons could not be obtained in a uniform 

 manner by the mere mixture of plumbago and clay in determinate doses. But they 

 discovered a remedy for this defect in the use of saline solutions, more or less con- 

 centrated into which they plunged the pencils, in order to modify their hardness and 

 increase the uniformity of their texture. The non-deliquescent sulphates were pre- 

 ferred for this purpose ; such as sulphate of soda, &c. Even syrup was found useful 

 in this way. 



PEWS, STEEXi, AND OF OTHER METALS. As peculiar elasticity is required in 

 these pens, now so commonly used, the best metal, made from either Dannemora- or 

 hoop-iron, is selected and laminated into slips about 3 feet long and 4 inches broad, of 

 a thickness corresponding to the desired thickness and flexibility of the pens. These 

 slips are subjected to the action of a stamping-press, somewhat similar to that for 

 making buttons. (See BUTTON ; PLATED WARE.) The point destined for the nib 

 is next introduced into an appropriate gauged hole of a little machine, and pressed 

 into the semi -cylindrical shape ; where it is also pierced with the middle slit and the 

 lateral ones, provided the latter are to be given. The pens are now cleaned, by being 

 tossed about among each other in a tin cylinder, about 3 feet long and 9 inches in 

 diameter, which is suspended at each end upon joints to two cranks, formed one on 

 each of two shafts. The cylinder, by the rotation of a fly-wheel, acting upon the 

 crank-shafts, is made to describe such revolutions as agitate the pens in all directions, 

 and polish them by mutual attrition. In the course of four hours several thousand 

 pens may be finished upon this machine. 



When steel pens have been punched out of the softened sheet of steel by the appro- 

 priate tool, fashioned into the desired form, and hardened by ignition in an oven 

 and sudden quenching in cold water, they are best tempered by being heated to the 

 requisite spring-elasticity in an oil-bath. The heat of this bath is usually judged of 

 by the appearance to the eye ; but this point should be correctly determined by a 

 thermometer, according to the scale (see STEEL) ; and then the pens would acquire 

 a definite degree of flexibility or stiffness, adapted to the wants and wishes of the con- 

 sumers. 



The following description of the pens made at the works of the late Joseph Gillott, 

 Birmingham, will illustrate the entire manufacture: 



The steel is procured at Sheffield ; it is cut into strips, and the scales removed by 

 immersion in pickle composed of dilute sulphuric acid. It is passed through rollers, 

 by which it is reduced to the necessary thickness ; it is then in a condition to be made 

 into pens, and is for this purpose passed into the hands of a girl, who is seated at a 



