| | PAGE |
| [Frontispiece], “Stone Age Calculating” | |
| One of the Pascal Machines | [10] |
| Photo of Blaise Pascal | [11] |
| Parmelee Patent Drawings | [16] |
| Hill Patent Drawings | [23] |
| Chapin Patent Drawings | [28] |
| From the Stark Patent Drawings | [32] |
| From the Robjohn Patent Drawings | [36] |
| From Drawings of Bouchet Patent 314,561 | [40] |
| Drawings of Spalding Patent No. 293,809 | [46] |
| “Macaroni Box” Model | [53] |
| Photo of Dorr E. Felt | [55] |
| The First “Comptometer” | [57] |
| From Drawings of Felt Patent No. 371,496 | [58] |
| Bill for First Manufacturing Tools of the Comptometer | [68] |
| Early Comptometer | [69] |
| Letter from Geo. W. Martin | [71] |
| Testimonial | [72] |
| Testimonial | [73] |
| Letters from Elliott and Rosecrans | [74] |
| From Drawings of Barbour Patent No. 133,188 | [78] |
| From Drawings of Baldwin Patent No. 159,244 | [83] |
| Baldwin Machine | [83] |
| From Drawings of Pottin Patent No. 312,014 | [88] |
| From Drawings of Burroughs Patent No. 388,118 | [94] |
| Photo of Wm. S. Burroughs | [95] |
| Drawings of Ludlum Patent No. 384,373 | [104] |
| From Drawings of Felt Patent No. 405,024 | [112] |
| Testimonial | [117] |
| Felt Recording and Listing Machine | [118] |
| From Drawings of Felt Patent No. 465,255 | [121] |
| Felt Tabulator | [126] |
| One of the Early “Comptographs” | [130] |
| Photo of Gottfried Wilhelm Leibnitz | [132] |
| Leibnitz Calculator | [133] |
| From Drawings of Burroughs’ Patents Nos. 504,963 and 505,078 | [136] |
| Burroughs’ Recorder | [137] |
| From the February 1908 Issue of Office Appliances Magazine | [142] |
| The High-Speed Calculator | [148] |
| Two Pages from Wales Adding Machine Co. Booklet | [165] |
| Moon-Hopkins Billing and Bookkeeping Machine | [176] |
| Napier’s Bones | [179] |
| From Drawings of Barbour Patent No. 130,404 | [180] |
| Photo of John Napier | [181] |
| From Drawings of Bollee Patent No. 556,720 | [186] |