THE MATHEMATICAL PRACTITIONERS 15 The Rittenhouse Brothers 15 Andrew Ellicott 19 Owen Biddle 21 Benjamin Banneker 22 Joel Baily 24 Reverend John Prince 24 Amasa Holcomb 26 INSTRUMENTS OF METAL 27 Pre-Revolutionary Immigrant Makers 27 Post-Revolutionary Immigrant Makers 30 Native American Makers 33 New Hampshire 34 Vermont 34 Massachusetts 36 Rhode Island 43 Connecticut 45 Ohio 49 New York 51 New Jersey 53 Delaware 54 Maryland and Virginia 54 Pennsylvania 58 INSTRUMENTS OF WOOD 65 The Use of Wood 65 Surviving Instruments 69 Compass Cards 75 Trade Signs 75 The Makers 80 Joseph Halsy 80 James Halsy II 84 Thomas Greenough 85 William Williams 93 Samuel Thaxter 97 John Dupee 104 Jere Clough 105 Andrew Newell 106 Aaron Breed 107 Charles Thacher 107 Benjamin King Hagger 109 Benjamin Warren 112 Daniel Burnap 117 Gurdon Huntington 118 Jedidiah Baldwin 123 Thomas Salter Bowles 124 THE NEW ERA 130 THE NATIONAL COLLECTION 131