40 Mint balance built by Joseph Saxton, about 1835 78 



41 Redheffer's perpetual motion machine 81 



42 Nathan Sellers (175 1 -1 830) 89 



43 Wire draw-bench, about 1830 91 



44 Dickinson cylinder paper machine, 181 7 97 



45 Handmade-paper mill 103 



46 Paper mold and deckel 104 



47 Paper-drying loft 105 



48 Screw press for paper 106 



49 Packet ship Hibernia 109 



50 Broadside of Thames tunnel, 1827 113 



51 Bryan Donkin ( 1 768-1855) r 17 



52 Fourdrinier paper machine, about 1850 119 



53 Sellers pulp dresser, 1832 120 



54 John Dickinson (1 782-1869) 123 



55 Saxton's locomotive differential pulley 132 



56 Perkins's cone-joint 133 



57 Saxton's magnetoelectric machine 134 



58 Map of Pennsylvania, showing system of canals and railroads 145 



59 Details of "Clarence" rail and roadbed 149 



60 Details of roadbed of Phi'adelphia and Columbia Railroad 151 



61 Belmont inclined plane on Philadelphia and Columbia Railroad ... 155 



62 Grade crossing on Philadelphia and Columbia Railroad 156 



63 Roadbed of abandoned portage railroad 157 



64 Sectional iron canal boats, 1839 158 



65 Baldwin locomotive, 1834 161 



66 Baldwin's half-crank 162 



67 English locomotive, John Bull, 1831 163 



68 Advertisement of Moses Starr & Son, boilermakers 165 



69 Device for "Increasing the adhesion of the Wheels of Locomotives" ... 173 



70 Thomas Rogers (1 792-1 856) 174 



71 Side support for Sellers locomotive 174 



72 Matthias W. Baldwin (1 795-1 866) 175 



73 Baldwin's locomotive wheel 177 



74 Baldwin's conical steam joint 178 



75 Advertisement of Coleman Sellers & Sons, locomotive builders 1 79 



76 Baltimore & Ohio locomotive Arabian 181 



77 Phineas Davis's steam-operated blower fan for locomotives 183 



78 Baldwin's stationary steam engine, 1829 186 



79 Leather splitting machine, 1809 187 



80 SethBoyden (1788-1870) 188 



81 Locomotive Orange, 1837, built by Seth Boyden 189 



82 Stephen Harriman Long (1784- 1864) 191 



83 Joseph Saxton (1799-1873) 192 



IX 



