The best Quotations

Do you know the writers of the following quotations?

Quotation Perpetual pushing and assurance put a difficulty out of countenance and make a seeming difficulty gives way. - writer
Quotation Much smoking kills live men and cures dead swine. - writer
Quotation A learned fool is more foolish than an ignorant one. - writer
Quotation Anyone who has passed through the regular gradations of a classical education, and is not made a fool by it, may consider himself as having had a very narrow escape. - writer
Quotation All human actions are equivalent... and all are on principle doomed to failure. - writer
Quotation They understand but a little who understand only what can be explained. - writer