Page:Popular Science Monthly Volume 6.djvu/103

Rh The first outcome of Priestley's chemical work, published in 1772, was of a very practical character. He discovered the way of impregnating-water with an excess of "fixed air," or carbonic acid, and thereby producing what we now know as "soda-water"—a service to naturally, and still more to artificially, thirsty souls, which those, whose parched throats and hot heads are cooled by morning draughts of that beverage, cannot too gratefully acknowledge. In the same year Priestley communicated the extensive series of observations which his industry and ingenuity had accumulated, in the course of four years, to the Royal Society, under the title of "Observations on Different Kinds of Air"—a memoir which was justly regarded of so much merit and importance, that the society at once conferred upon the author the highest distinction in their power, by awarding him the Copley Medal.

In 1771 a proposal was made to Priestley to accompany Captain Cook in his second voyage to the South Seas. He accepted it, and his congregation agreed to pay an assistant to supply his place during his absence. But the appointment lay in the hands of the Board of Longitude, of which certain clergymen were members; and whether these worthy ecclesiastics feared that Priestley's presence among the ship's company might expose his majesty's sloop Resolution to the fate which aforetime befell a certain ship that went from Joppa to Tarshish, or whether they were alarmed lest a Socinian should undermine that piety which, in the days of Commodore Trunnion, so strikingly characterized sailors, does not appear; but, at any rate, they objected to Priestley, "on account of his religious principles," and appointed the two Forsters, whose "religious principles," if they had been known to these well-meaning but not far-sighted persons, would probably have surprised them.

In 1772 another proposal was made to Priestley. Lord Shelburne, desiring a "literary companion," had been brought into communication with Priestley by the good offices of a friend of both—Dr. Price—and offered him the nominal post of librarian, with a good house and appointments, and an annuity in case of the termination of the engagement. Priestley accepted the offer, and remained with Lord Shelburne for seven years, sometimes residing at Calne, sometimes traveling abroad with the earl.

Why the connection terminated has never been exactly known, but it is certain that Lord Shelburne behaved with the utmost consideration and kindness toward Priestley; that he fulfilled his engagements to the letter; and that, at a later period, he expressed a desire that he should return to his old footing in his house. Probably enough the politician, aspiring to the highest offices in the state, may have found the position of the protector of a man, who was being denounced all over the country as an infidel and an atheist, somewhat embarrassing. In fact, a passage in Priestley's "Autobiography," on