The Reformation and the French Revolution are cases in point.

And what a principal part do these two great events always play in any speculations instituted subsequent to them! How easy it is to see whether a writer lived before the Reign of Terror, or after it, from his gait and manner of approaching social inquiries! Is there any reason to suppose that such mutations are now at an end?
None.

The probability, well nigh a certainty, is that metamorphoses of the social organism are in store for us which will equal, if they do not vastly exceed, anything that the past has offered.
Considerations of this kind need to be kept in view if we would be just in our appreciation of historical writings which have already a certain age.

It is impossible that a history composed a century ago should fully satisfy us now; but we must beware of blaming the writer for his supposed or real shortcomings, till we have ascertained how far they arose from his personal inadequacy to his task, and were not the result of his chronological position.

It need not be said that this remark does not refer to many books which are called histories, but are really contemporary memoirs and original authorities subservient to history proper.