Vigesimal

"For indeed, looking at the activity of the historic Pen and Press through this last half-century, and what bulk of History it yields for that period alone, and how it is henceforth like to increase in decimal or vigesimal geometric progression,—one might feel as if a day were not distant, when perceiving that the whole Earth would not now contain those writings of what was done in the Earth, the human memory must needs sink confounded, and cease remembering!— […]"

"To go on by hands and feet to 20, and thence to reckon by twenties, is a vigesimal notation. Now though in the larger proportion of known languages, no distinct mention of fingers and toes, hands and feet, is observable in the numerals themselves, yet the very schemes of quinary, decimal and vigesimal notation remain to vouch for such hand-and-foot counting having been the original method on which they were founded."

"If the years of the incomplete century be divided into twenties, and the excess of twenties resolved into fours, the Dominical Letter will advance three places for every twenty, two places for every four, and six places for every unit of the still outstanding remainder. Hence the Sunday Letter will be found by taking the sum of four numbers, which may be called the centurial, the vigesimal, the quaternial, and the residual."