I shall not then, reverend sir, make you my confessor in matters of religion, but I will disclose to you my opinion, as a man of letters, on the composition of your book. Having in former days, read many works of theology, I was curious to learn whether by any chemical process you had discovered real beings in that world of invisibles. Unfortunately, I am obliged to declare to the public, which, according to your expression, p. 19, "hopes to be instructed, to be led into truth, and not into error by me," that I have not found in your book a single new argument, but the mere repetition of what is told over and over in thousands of volumes, the whole fruit of which has been to procure for their authors a cursory mention in the dictionary of heresies. You everywhere lay down that as proved which remains to be proved; with this peculiarity, that, as Gibbon says, firing away your double battery against those who believe too much, and those who believe too little, you hold out your own peculiar sensations, as to the precise criterion of truth; so that we must all be just of your size in order to pass the gate of that New Jerusalem which you are building. After this, your reputation as a divine might have become problematical with me; but recollecting the principle of the association of ideas so well developed by Locke, whom you hold in estimation, and whom, for that reason I am happy to cite to you, although to him I owe that pernicious use of my understanding which makes me disbelieve what I do not comprehend--I perceive why the public having originally attached the idea of talents to the name of Mr. Priestly, doctor in chemistry, continued by habit to associate it with the name of Mr. Priestly, doctor in divinity; which, however, is not the same thing: an association of ideas the more vicious as it is liable to be moved inversely.* Happily you have yourself raised a bar of separation between your admirers, by advising us in the first page of your preface, that your present book is especially destined for believers. To cooperate, however, with you, sir, in this judicious design, I must observe that it is necessary to retrench two passages, seeing they afford the greatest support to the arguments of unbelievers. * Mr. Blair, doctor of divinity, and Mr. Black, doctor in chemistry, met at the coffee house in Edinburg: a new theological pamphlet written by doctor Priestly was thrown upon the table, "Really," said Dr. Blair, "this man had better confine himself to chemistry, for he is absolutely ignorant in theology:"--"I beg your pardon," answered Dr. Black, "he is in the right, he is a minister of the gospel, he ought to adhere to his profession, for in truth he knows nothing of chemistry."