THE BOOKSELLER's ADVERTISEMENT

The following Discourse came into my Hands perfect and entire. But there being several Things in it, which the present Age would not very well bear, I kept it by me some Years, resolving it should never see the Light. At length, by the Advice and Assistance of a judicious Friend, I retrench’d those Parts that might give most Offence, and have now ventured to publish the Remainder; Concerning the Author, I am wholly ignorant; neither can I conjecture, whether it be the same with That of the two foregoing Pieces, the Original having been sent me at a different Time, and in a different Hand. The Learned Reader will better determine; to whose Judgment I entirely submit it.

A DISCOURSE CONCERNING THE MECHANICAL OPERATION OF THE SPIRIT, &c.

For T. H. Esquire, at his Chambers in the Academy of the Beaux Esprits in New-Holland.

Sir,

It is now a good while since I have had in my Head something, not only very material, but absolutely necessary to my Health, that the World should be informed in. For, to tell you a Secret, I am able to contain it no longer. However, I have been perplexed for some time, to resolve what would be the most proper Form to send it abroad in. To which End, I have three Days been coursing thro’ Westminster-Hall, and St. Paul's Church yard, and Fleet-street, to peruse Titles; and, I do not find any which holds so general a Vogue, as that of A Letter to a Friend:Nothing is more common than to meet with long Epistles address’d to Persons and Places, where, at first thinking, one would be apt to imagine it not altogether so necessary or Convenient; Such as, a Neighbour at next Door, a mortal Enemy, a perfect Stranger, or a Person of Quality in the Clouds; and these upon Subjects, in appearance, the least proper for Conveyance by the Post; as, long Schemes in Philosophy; dark and wonderful Mysteries of State; Laborious Dissertations in Criticism and Philosophy, Advice to Parliaments; and the like.