40 BENJ. PIKE'S, JR., DESCRIPTIVE CATALOGUE. 



well as oblique ones, with more ease and expedition than by 

 the common parallel rule. 



Price, 75 cts. to $2.50. 



with steel blade, $3.00 to $5.00. 



The T Square and Protractor. (Fig. 43, page 39.) 

 This instrument is formed of a divided arc of brass, usually 

 about ten inches in diameter, whose graduation commences 

 at the middle, and is continued each way to 90 degrees ; at 

 the centre of the arc is attached a movable arm, about 30 

 inches long ; at the shorter end is a vernier, running on the 

 graduated arc, and subdividing the degrees of the arc into 

 minutes, and having a spring bent over to the under side of 

 the arc, with a screw to clamp it fast in any position. Used 

 on a true drawing board, this instrument is simple and con- 

 venient, answering all the purposes of plotting and protract- 

 ing of a square and bevel, and for drawing parallel lines in 

 different directions. Price, $7.00 to $12.00. 



Gauge for measuring Diameters, Interiors, etc. (Fig. 44, 

 page 39), with steel blades and brass sliding bars, the bars 

 sliding within each other, and graduated to inches and 

 tenths, with one, two, or three slides. 



Price, $1.50 to $7.50. 



Draughtsman's Squares. (Figs. 45 and 46, page 39.) 

 These squares are best made of hard wood, and are used 

 with a common flat ruler, one of the edges of the square 

 being placed against the rule, and by holding the rule fast, 

 and moving the square, parallel lines may be drawn with 

 ease and accuracy. One of the squares represented is a 

 solid one, having a hole for the finger to move it by. The 

 other is open in the centre, and is used where they are 

 required of a large size. 



Price 25 cents to 75 cents. 



Curves. (see pages 41, 42, 43.) These are various in 

 shape and size, and from to 24 inches long. Their use is 

 to present a variety of forms for drawing curves, and they 

 are extensively used in naval architecture and other draw- 

 ings. Price, 38 cents to 50 cents each. 

 . The set of 25, $7. 



