The 16 pages of the ciphering book relating to the arithmetical education of Osborne comprise pages 21 through 32. (Of these pages, page 28 is blank and the upper halves of pages 21-22, 25-26, and 31-32 have been cut or torn away.) These pages are on good quality paper made by Thomas and Mark Willcox at their Ivy Mills in Pennsylvania (now Delaware). The watermarks in this paper are the initials TMW and the figure of a dove holding a leafless olive branch. They contain problems concerning the reductions to farthings and pence of several kinds of money including pounds, pistoles, guineas, moidores, crowns, johannes, doubloons, dollars, crusadoes, and reales. They contain, too, problems in troy weight and avoirdupois weight. None of Osborne's exercises are dated. At the same time, they are the sorts of arithmetical problems thought fit to be set for a boy of 9 or 10 years of age. It is presumed that the exercises were set for young Osborne while he was being educated at home-probably about 1753.

Sloan's exercises are found on 26 pages of the ciphering book. Some exercises are dated in November 1778, and January and February 1779. All of them involve various units of measure: troy weight, apothecaries' weight; avoirdupois weight, liquid measure, dry measure, long measure, time, and money. The first three pages are devoted to addition; pages 4-5 to subtraction; pages 7-10 to multiplication; and pages 11-15 to division. On pages 33-42 are set problems for the student concerning the division of sums of money among differing numbers of men, reduction of different monies to farthings and pence, and tare and tret. Young Sloan died at the age of 14, and his ciphering book passed into the possession of his sister Jane (Mrs. Jacob Fisher of Salisbury, N.C.). As succeeding generations of Mrs. Fisher's descendants moved from state to state (Alabama, Arkansas, Louisiana, Mississippi, etc.), the manuscript traveled with them, coming to rest, finally, with the present donor in California. At some point in its migration, the manuscript was used by a rattlesnake as an aid in shedding its skin. When the snake wriggled between the pages of the booklet, it shed the skin over its rattles between pages 16 and 17.

The blank sheets added by Osborne c. 1778 are of an inferior quality and are marked with the standard English symbols used by papermakers at the time: one side having the figure of Britannia seated in a fenced ground holding in her hand a liberty pole surmounted by a Phrygian cap, and a lion rampant with the motto Pro Patria above the image, and the other side having the royal cypher in an heraldic garter.