But at that particular moment Rush was too much engaged in combating yellow fever, which again ravaged Philadelphia, and all who could, fled, and the streets were "lifeless and dead." The prevalence of this fearful plague was a potent factor in Priestley's failure to visit the City during the year--the last year of a closing Century which did not end in the prosperity anticipated for it in the hopeful months and years following the war. It seemed, in many ways, to be the end of an era. Washington died December 14, 1799, and the Federalists' tenure of power was coming to a close. The Jeffersonians, aided by eight of the electoral votes of Pennsylvania, won the victory, amid outbursts of unprecedented political bitterness. It was, therefore, very wise that the Doctor remained quietly at home in Northumberland with his experiments and Church History. The new Century--the 19th--found our beloved philosopher at times quite proud of the success he had with his experiments and full of genuine hope that "phlogiston" was established; and again dejected because of the "coarse and low articles" directed against him by the prints of the day. To offset, in a measure, the distrust entertained for him because of the "intercepted letters" he addressed a series of _Letters_ to the inhabitants of Northumberland and vicinity. These were explanatory of his views. At home they were most satisfying but in the city they brought upon him "more abuse." And, so, he translated a passage from Petrarch which read-- By civil fueds exiled my native home, Resign'd, though injured, hither I have come. Here, groves and streams, delights of rural ease; Yet, where the associates, wont to serve and please; The aspect bland, that bade the heart confide? Absent from these, e'en here, no joys abide. And these were incorporated in his brochure. Having alluded to the _Letters_ addressed to the Northumberland folks, it may be proper to introduce a letter which Priestley received from Mr. Jefferson, whom the former was disposed to hold as "in many respects the first man in this Country:" Philadelphia, Jan. 18, 1800. Dear Sir-- I thank you for the pamphlets (Letters) you were so kind as to send me. You will know what I thought of them by my having before sent a dozen sets to Virginia, to distribute among my friends; yet I thank you not the less for these, which I value the more as they came from yourself. The papers of Political Arithmetic, both in yours and Mr. Cooper's pamphlets, are the most precious gifts that can be made to us; for we are running navigation-mad, and commerce-mad, and Navy-mad, which is worst of all. How desirable it is that you should pursue that subject for us. From the porcupines of our country you will receive no thanks, but the great mass of our nation will edify, and thank you.