122 



DRAWING INSTRUMENTS. 



Drawing 

 Inm- 



incnu. 



PLATE 



crx.\\\ n. 



V.K-. 'it- 



Fig. 7. 



Dciikin'i 

 patent steel 

 pen. 

 Fig. 23. 



tliey should be quit* sharp at tin- edge, otherwise they 

 will not make a regular line. i^ a MTV good 



kind of steel pen, consistingof two steel blades, put to- 

 gether by a rivet at a, and secured In a brass or silver 

 cap b screwed u|x>n the upper end, where the cxtremi- 

 both Made* being laid together, are cut into one 

 crew, as shewn at . The lower part of the 



blades has a milled screw il, which draws them 

 ther, to adjust the distance of the points e. When the 

 pen requires sharpening, the screw d is taken out, the 

 cap l> screwed on, ana then the two blades may be 



d out like scissors, on the cmtre rivet a, as shewn 

 in l'ig -'". to excise the inside surfaces of the points e. 

 The jKiint- of all pens should be hardened and temper- 

 ed ; but they will in time grow blunt at the edges, 

 by constant use, and must then be repaired, by rubbing 

 them tijx>n a hone to sharpen the edges again. In do- 

 ing this, great care must be taken that both points are 

 made to correspond both in length and breadth. Some 

 pens are made with a joint to unite the two blades toge- 

 ther, as shewn applied to the compasses, Figs. 3. and 8, 

 and these have a small spring between them, to force 

 them open. The screw for adjustment is the same as 

 the fonner. The pen of the pocket compasses, Fig. 7, 

 is adjusted by means of a sliding ring n fitted over the 

 two nalves of it, because there is in this case no room 

 for a screw, when the pen is inserted into the hollow 

 of the leg of the compasses. By sliding the ring down 

 towards the point, the pen is closed up ; or, by sliding 

 it upwards, the points are suffered to open. The same 

 mode of adjustment may be used for a drawing pen. 



Fig. 23. is one of Mr Donkin's patent steel pens, 

 which is intended for writing ; but as it is a useful in- 

 strument for drawing, we introduce it here. The other 

 kind of steel pen is as perfect as can be wished, for 

 drawing straight or regularly curved lines, where some 

 guide is used tor it ; but it will not do for those lines 

 which are to be drawn by the hand, unassisted by a 

 ruler, or other means of directing the pen. It is the 



practice to draw such lines with a crow, or goose 

 quill pen ; but they can be much more neatly executed 

 by Mr Donkin's, which is the best writing steel pen 

 that has appeared. The nip or point consists of two 

 pieces of thin steel plate a, a, put together nearly at 

 right angles to each other; and the part where they 

 meet is mitred, to make a joint for the slit of the pen, 

 which is quite close, except when the pen is writing, 

 and then the pressure bends the blades, and causes the 

 joint to open sufficiently to deliver the ink ; therefore, 

 in proportion ns this pressure is increased, the line be- 

 comes broader, in the same manner as the common goose 

 quill pen, but with the advantage of being much more 

 da-tic in the blades of the nip, because they are filed 

 very thin just above the point. The pen writes finer 

 than a quill does, except the minute after being mend- 

 ed, because the jwints are made of a very hard sub- 

 stance ; and when once made up carefully to write or 

 draw fine, will not speedily wear out. The two p 

 of steel a, a, composing the nip, are united, by being 

 soldered to a piece of metal, and this fits in the silver 

 tube d, which forms the handle. The shape of the 

 point which writes is not easily described ; but may be 



lered as similar to the point of a quill writing pen 

 of the best form, except that the two pieces which form 

 the nip are not portions of a cylindric tube, but two 

 flat plates situated at right angles to each other ; and it 

 is this circumstance which gives it the superiority over 

 otlu r steel writing pens, because the flat .sides are \ i ry 

 clastic, and bend freely ; but a portion of a tube cannot 



spring readily, however elastic its substance may be. Drawing 



The thin pl.'i before mentioned, just alkive the nip, is liru- 

 reduced by filing from the inside, to allow the points 

 to spring ami i> of farther BM, to form a .-light cavity ' "~ Y ~"" 

 where the ink re-ts. and i- ready to pa-s down t. 

 pajx-r the illst.int the slit of the pen is < 

 sing on the paper. The handle of the p.-n is made of 

 three tubes, d, r, and f, which shut one into the other, 

 for portability ; but when drawn out, as in the Figure, ], ATE 

 forma .-uliicient handle to write with. The point of C CXXXVII. 

 the pen, as shewn separate at :, draws <m t of the lo\v ( : 

 end of the external tube it, and Ix-ing inverted, and 

 thrust in, is secure from injury ; and thus the pen re- 

 quires no other sheath when carried in the pocket. 

 When a pen of this kind is used lot- drawing, it- [mint 

 must be very carefully made sharp, by rubbing it upon 

 an oilstone, and it will draw better than any other for 

 such lines, as the steel drawing pen will not execute. 



Kulers for accurate purposes should be made of steel Rolen. 

 or brass; but as these are liable to contract, tamish, or 

 rn-t. ,,nd then soil the paper, WCKK! and ivory are pre- 

 ferred for general purposes ; still no artist should be 

 without accurate brass or steel rulers of considerable 

 length, to lay down his principal lines, and to verify 

 his smaller rulers. A convenient standard brass ruler 3,,^. 

 may be two feet and a half in length, and have inches 

 and decimals accurately divided ujwn one edge of it, 

 and decimals of a foot upon the other. One edge should 

 be bevelled or made sharp to draw lines by, and the 

 other left the full thickness of the ruler, but both should 

 be very exactly straight. When rulers are made of 

 wood, it should be of a hard texture, such as mahoga- \\voi. 

 ny, box, beef wood, or ebony, and pieces should be 

 carefully selected which have a clean straight graii 

 these are the least liable to warp. The edges which 

 are to be used to draw the pen against should be al- 

 v, ays bevelled, and very smooth. To verify the edge of 

 a ruler, a very fine line should be drawn by it, taking 

 great care to hold the pen perpendicular, and apply it 

 fairly, then move the ruler to the opposite side of the 

 line so drawn, and reversing it end for end, that the 

 same edge of the ruler corresponds with the line, exa- 

 mine if it does exactly correspond in the whole length, 

 which it cannot, unless both the edge and the line 

 very straight ; because this mode f trial doubles the 

 quantity of the error, and therefore renders the smallest 

 deviation apparent. Ivory is the best substance for Ivory, 

 small rulers and divided scales, because being so smooth, 

 the drawing pun slides freely against it, and draws beau- 

 tiful lines: The divisions also, when filled with black, 

 are more apparent to the eye than on any other sub- 

 stance. The only objection to it is, the liability to warp 

 on every change of weather ; but if carefully selected, 

 some pieces may be found to preserve a very straight 

 edge under all circumstances. These are to be sought 

 among those which are cut from the centre of the tooth, 

 having the grain of the ivory radiating each way from 

 the centre of the ruler to the edges, to appear something 

 like the feather of a quill ; in this case, both edges be- 

 ing of similar texture, they expand or contract equal- 

 ly, by the moisture or dryness of the atmosphere, and 

 therefore do not change their figure. Scales of this Plotting 

 kind, and about 1'2 inches in length, are extremely use- Kale*, 

 fill when divided, as shewn in Fig. ]";. These are pjg. 15. 

 called plain or plotting scales, and are divided into 10 

 and '20 'M and 10, or .M) and GO per inch, as the artist 

 requires. They are much more accurate for draw ing 

 than a scale made on the paper, and more convenient, 

 because the divisions coming to the edges of the scale, 



