The greatest cold at Philadelphia, during the same days of January, 1776, was at 17°, but the mercury rose there, on one of those days, to 48°. The _mean_ degree of cold at Philadelphia, in this corresponding period of time, was 29⅓°; being about 2½° warmer (or rather, less cold,) than the general temperature of the weather in London, at the same time, in what was there called a “severe frost.” Eighty-five degrees of Fahrenheit’s scale is considered as a very extraordinary heat, in London: consequently, a range of 68° may be presumed to reach the extremes of heat and cold in England, in the latitude of nearly 52° N.[98a] Notwithstanding the extremes of heat and cold, which thus appear in the climate of Pennsylvania, Mr. Jefferson remarks (in his _Notes on Virginia_,) that these extremes are greater at Paris than at Williamsburg, the hottest part of Virginia. Yet Williamsburg, which is only about 2¾° to the southward of Philadelphia, is nearly 11¾° further south than Paris. Footnote 98a: Since writing the above, the author has ascertained, that in London, during the four last years of the last century, Six’s thermometer, out of doors, averaged 49.6; that on the hottest day within that period, the mercury rose to 86; and that it fell, on the coldest day, to 4. Footnote 99: See a description of this Chronometer, in the Appendix. ----- The great accuracy and exquisite workmanship displayed in every thing belonging to the profession he pursued, that came through his hands, soon became pretty extensively known: and this knowledge of his mechanical abilities, assisted by the reputation he had already acquired as a mathematician and astronomer, in a short time procured him the friendship, respect and patronage, of some eminent scientific characters; while it promoted his interest, in the profession he had thus newly chosen. In this he was, nevertheless, _self-taught_; for he never received the least instruction from any person, in any mechanic art whatever: and, therefore, if he were to be considered as being merely an excellent artist, in an occupation intimately connected with the science of mathematics—_untutored_, as he was, in any art or science,—he would deservedly be deemed an extraordinary and eminent man. It will be perceived, however, that it was the _union_ of the almost unbounded powers of his genius, and his prodigious acquirements in a sublime science, with his wonderful abilities as a philosophical mechanic—and these faculties and attainments, moreover, combined with an amiable and virtuous character,—which constituted that celebrity so justly attached to his name.