MATHEMATICAL INSTRUMENTS. 5 



No. 



70 Fig. 40, Eckhardt's rolling parallel rule, 



twelve inch, 5.50 



71 Fig. 41, T squares, of hard wood, twenty- 



four to thirty-six inches long, 75 cts. to 1.50 



72 Fig. 41, T squares, of hard wood, nine to 



eighteen inches long, - 38 cts. to 1.00 



73 Fig. 42, T squares of hard wood, twenty-four 



to thirty-six inches with level and screw, 



$1.50 to 2.50 



74 Fig. 42, T squares, with steel blade, twenty- 



four to thirty-six inches, $3.50 to 5.50 



75 Fig. 43, T squares, with protractor in brass, 



$7 to 12.00 



76 Fig. 43, T squares, with protractor, in Ger- 



man silver, - - $9 to 18.00 



77 Fig. 44, squares and gauge for measuring di- 



ameters, interiors, &c., - - $1.50 to 7.00 



78 Fig. 45, draughtsmen's squares, of hard 



wood, solid, - 25 cts. to 0.50 



79 to 106 Fig. 46, draughtsmen's squares of hard 



wood, open, 62 cts. to 1.50 



107 Fig. 47 to Fig. 73, curves of various shapes, 



in hard wood, 25 cts. to 0.50 



108 Fig. 47 to Fig. 73, set of twenty-seven curves 



of various shapes, - - 7.00 



109 Fig. 74, centrolinead, right and left, each, 10.00 



110 Fig. 75, best circular protractor, 6 to 12 inch 



diameter, $18 to 40.00 



111 Fig. 76, pantagraph in ebony, with brass 



mounting, - - $ 7. 50 and 14. 00 



112 Fig. 76, pantagraph in brass, - 15.00 to 40.00 



113 Gunther's one foot scales, - 38.00 



114 Gunther's two foot scales, 0.63 



115 Two foot box scales, divided in twelfths, from 



one-eighth to one inch, 1.75 



116 One foot box scale, ,.:.-,.' 1.25 



117 Wantage rods, - $38 cts. to $0.63 



118 Gauging rods, - 75 cts. to 2.00 



119 Gauging callipers, - $6 to 8.50 



120 Yard sticks, graduated both sides, 25 cts. to 0.50 



121 Whalebone pocket measures, very elastic, one 



to three feet, - - - $1 to 2.00 



