But among the writings of this great and good man is an Essay of the most curious character, illustrating his weakness upon the point in question, and entitled, “Siris, a Chain of Philosophical Reflections and Inquiries concerning the Virtues of tar water, and divers other Subjects,”—­an essay which begins with a recipe for his favorite fluid, and slides by gentle gradations into an examination of the sublimest doctrines of Plato.  To show how far a man of honesty and benevolence, and with a mind of singular acuteness and depth, may be run away with by a favorite notion on a subject which his habits and education do not fit him to investigate, I shall give a short account of this Essay, merely stating that as all the supposed virtues of Tar Water, made public in successive editions of his treatise by so illustrious an author, have not saved it from neglect and disgrace, it may be fairly assumed that they were mainly imaginary.

The bishop, as is usual in such cases, speaks of himself as indispensably obliged, by the duty he owes to mankind, to make his experience public.  Now this was by no means evident, nor does it follow in general, that because a man has formed a favorable opinion of a person or a thing he has not the proper means of thoroughly understanding, he shall be bound to print it, and thus give currency to his impressions, which may be erroneous, and therefore injurious.  He would have done much better to have laid his impressions before some experienced physicians and surgeons, such as Dr. Mead and Mr. Cheselden, to have asked them to try his experiment over again, and have been guided by their answers.  But the good bishop got excited; he pleased himself with the thought that he had discovered a great panacea; and having once tasted the bewitching cup of self-quackery, like many before and since his time, he was so infatuated with the draught that he would insist on pouring it down the throats of his neighbors and all mankind.

The precious fluid was made by stirring a gallon of water with a quart of tar, leaving it forty-eight hours, and pouring off the clear water.  Such was the specific which the great metaphysician recommended for averting and curing all manner of diseases.  It was, if he might be believed, a preventive of the small-pox, and of great use in the course of the disease.  It was a cure for impurities of the blood, coughs, pleurisy, peripneumony, erysipelas, asthma, indigestion, carchexia, hysterics, dropsy, mortification, scurvy, and hypochondria.  It was of great use in gout and fevers, and was an excellent preservative of the teeth and gums; answered all the purpose of Elixir Proprietatis, Stoughton’s drops, diet drinks, and mineral waters; was particularly to be recommended to sea-faring persons, ladies, and men of studious and sedentary lives; could never be taken too long, but, on the contrary, produced advantages which sometimes did not begin to show themselves for two or three months.