39

9

produced an algebra of logic which was
equivalent to the alpha part of existential
graphs; but he subsequently used it to
take important steps toward correcting
the doctrine of probabilities.

De Morgan had many pupils, and among
them Jevons who did some good work. I
took up the subject about 1860, and lectured
at this Institution upon it in 1866. I published
various papers relating to the beta
part of the subject, always employing some
modification of the Algebra of Boole which
I brought to perfection in Note B appended
to the Johns Hopkins Studies in Logic.

Meantime Schröder, beginning in 1877,