20.] To this class of bright Negroes belonged Thomas Fuller, a native African, who resided near Alexandria, Virginia, where he startled the students of his time by his unusual attainments in mathematics, despite the fact that he could neither read nor write.

Once acquainted with the power of numbers, he commenced his education by counting the hairs of the tail of the horse with which he worked the fields.

He soon devised processes for shortening his modes of calculation, attaining such skill and accuracy as to solve the most difficult problems.

Depending upon his own system of mental arithmetic he learned to obtain accurate results just as quickly as Mr.Zerah Colburn, a noted calculator of that day, who tested the Negro mathematician.[1] The most abstruse questions in relation to time, distance, and space were no task for his miraculous memory, which, when the mathematician was interrupted in the midst of a long and tedious calculation, enabled him to take up some other work and later resume his calculation where he left off.[2] One of the questions propounded him, was how many seconds of time had elapsed since the birth of an individual who had lived seventy years, seven months, and as many days.

Fuller was able to answer the question in a minute and a half.
[Footnote 1: Baldwin, _Observations_, p.