"Dr. Young, by his own confession, and for reasons... alluded to, was not adapted for a popular lecturer. His style was too compressed and laconic, and he had not sufficient knowledge of the intellectual habits of other men, to address himself prominently to those points of a subject where their difficulties were likely to occur. If... delivered nearly in the form in which they are printed, [the lectures] must have been generally unintelligible even to well-prepared persons, notwithstanding all the assistance which models, drawings, and diagrams could afford."