Some reminiscences of the history of electrophoresis.

Dole's and Longsworth's solution of the whole set of moving boundary equations by using the dimensionless transference numbers is reviewed. Longsworth's teachings on the nature of transference numbers and his pondering over transference numbers of proteins led the author to inquire why transference numbers of ampholytes were never measured. Logical reasoning on this subject led to the invention of isoelectric focusing.