She knows with unerring instinct what is right, and does it joyously.

He now entered, unaided save by his own unerring tact and vivid apprehension, upon a course of study which, in two years, placed him on a level with the greatest of his contemporaries.

Then with the unerring official memory that characterized him he repeated from the opening words of the manifesto:

In place of these straggling efforts of the unassisted human mind, a graduated system of helps was to be supplied, by the use of which the mind, when placed on the right road, would proceed with unerring and mechanical certainty to the invention of new arts and sciences.

At such moments of crisis it almost excelled human comprehension; the mind seems to have gathered to itself and summed up the balance of all human passions arranged for and against him, and to have calculated with unerring exactitude the consequences of each decision.