Details
Calculators:
an Addiator adding and subtraction machine in book-form case, with stylus; an Otis King, Model K, Scale 414 and another, Scale 429, with instructions, both in cartons; and two books, The Tutor's Assistant ... a Compendium of Arithmetic .... (Walkinghame, ed. Crosby, 1815) and Hoppus's Practical Measurer, n.d. (5)
an Addiator adding and subtraction machine in book-form case, with stylus; an Otis King, Model K, Scale 414 and another, Scale 429, with instructions, both in cartons; and two books, The Tutor's Assistant ... a Compendium of Arithmetic .... (Walkinghame, ed. Crosby, 1815) and Hoppus's Practical Measurer, n.d. (5)