18 



for the ink ; the blades may be opened more or less by a 

 screw, and being properly set, will draw an equal and regu- 

 lar line of any desirable thickness. One of the blades is 

 formed with a joint, but the points may be separated and 

 thus cleaned more conveniently. A small spring is some- 

 times inserted between the blades, to act against the mov- 

 able blade, and serves to steady it in drawing wide lines ; in 

 pens with metal handles there is usually inserted in the 

 middle part a fine point, which, when unscrewed, can be used 

 for making a nice dot, or mark, on paper ; or to set off 

 divisions from the protractor. Price, $1.25. 



The Steel Drawing Pen. (Fig. 10, page 19.) Is form- 

 ed of two blades of steel joined at the top, both immovable 

 except from the spring of the steel, and terminated with 

 very fine points. The screw in the middle of the blades 

 will draw the points close together, or allow them to sepa- 

 rate sufficiently to clean. This pen is mostly used for very 

 fine lines, and is mounted with an ivory handle. 



Price, $1.25. 



The Road Pen (Fig, 11, page 19), or double drawing 

 pen, is formed of two steel pens joined together with a 

 haHdle, and having a screw whereby they can be set nearer 

 or wider, at the pleasure of the drawer, and will draw two 

 parallel lines in any direction ; is much used in laying down 

 roads and canals, in drawings where they are required. 



Price, $3.00 and $3.50. 



The Dotting Pen. (Fig. 12, page 19.) This instrument 

 consists of two blades of metal, formed as the drawing pen, 

 one of which is jointed, and by loosening the screw may be 

 separated from the other at its point ; near the point of the 

 fixed blade is fastened a short pin, on which small indented 

 steel wheels of different figures can be placed, and allowed 

 to revolve freely when passed over paper ; it is fed with ink 

 from the blades over it, and communicates the same in equal 

 and regular dots, lines, ar a combination of dots and lines, 

 according to the figure of the wheels or rollers used. This 

 instrument is particularly useful where a number of courses 

 are to be laid down on one map or plan, and it is required 

 to distinguish each readily. It may also be used without 

 the rollers as a drawing pen for drawing very wide ink lines ; 



