OF DRAWING INSTRUMENTS. 85 



773. Bow Pens or Pencils, single joints, brass, Is. 6d. and 2s. 6d. each ; electrum 



046 



774. BEST DOUBLE-JOINTED INK OR PENCIL Bow, in electrum, each 080 



775. BEST DOUBLE-JOINTED INK OB PENCIL Bow, with points to hold needles, 



each 090 



776. STEEL SPRING Bows, in electrum (fg. 776), p. 83, the set of three forming ink, 



pencil, and divider, each . . . 076 and 10 6 



777. STEEL SPRING Bows, the points to hold needles, finest quality only 110 



If in maroon case, extra, Is. 6d. and 2s. 6d. 



778. Drawing Pens, best steel and electrum, with ivory handle 1 8 and 2 6 



779. DRAWING PENS with turn up nibs . . 030 and 040 



780. BORDERING OR COLOURING PEN, improved . 046 and 050 



782. Lithographic Pen . . . . 2 6 and 3 



783. RAILWAY OR ROAD PEN, best quality only . 060 



784. DOTTING OR WHEEL PEN, improved with set of wheels, very best 076 



785. NEEDLE PRICKER, with reserve for needles, improved . . 026 



786. TRACER .... . 016 



787. Opisometer or Map Metre, very convenient for measuring curved distances on 



maps (in case) ... ..036 



788. Six VERY BEST DRAWING PENS, assorted, to fit one handle in maroon case 



13 6 



789. LITHOGRAPHIC CROW QUILL OR MAPPING PEN, with handle, per dozen 020 

 Particular attention is requested to the excellence of all the above pens and the constant 



satisfaction they are giving. 



790. Centrolinead, improved, 42-inch, bar, with brass joints and studs 1 12 6 

 792. SEMI-ELLIPTIC TRAMMELS, of best make, brass, 2 10 ; electrum 330 



796. CAMERA LUCIDA, AND CLAUDE LORRAINE GLASSES, seeNos. 1567 and 1572. 



797. Eidograph, see No. 602. 



798. PENTAGRAPH, see Nos. 599 to 600. 



799. DRAWING BOAR DS, see Nos. 706 to 710. 



800. PAPER AND COLORS, see index. 



THE METRIC SYSTEM. 



On account of the importance attached by scientific and commercial men to the use 

 rf the metric system of weights and measures, and its gradual extension throughout 

 the world, and at the request of James Yates, Esq., F.R.S., the oldest and most active 

 vice-president of the association formed to aid in its universal adoption, the following 

 list of articles is here inserted. They are nearly all of English manufacture, and are 

 selected from an immense variety on account of their fitness for teaching the system 

 and their adaptation for use in scientific pursuits, in commerce, foreign and domestic, 

 and in trades and employments of every kind. 



