A narrative of the two aerial voyages of doctor Jeffries with mons. / John Jeffries . Blanchard; with meteorological observations and remarks. The first voyage, on the thirtieth of november, 1784, from London into Kent : the second, on the seventh of january, 1785, from England into france. By doctor Jeffries. Presented to the royal society, april 14, 1785; and read before them, january, 1786