It was arranged to record the observations on ruled paper with a silver pen, because the doctor would not trust a common pen or pencil as liable to accident. He also had a map of England to determine the direction which the balloon took. Jeffries' English sentiments are shown by this quotation from his narrative: "I had provided a handsome British flag, invidiously represented the next day in one of the public papers to have been the flag of the American States." The barometer and thermometer were observed every few minutes, and the hygrometer occasionally. The electrometer did not change its indications. Samples of air were obtained and sent to the Royal Society, but it does not appear that they were ever analyzed. The balloon rose nearly two miles, and descended safely in Kent after an hour and a half. Jeffries' observations compare favourably with those made until recently; indeed, for nearly a century there was little improvement in the apparatus. The decrease of temperature which Jeffries found, viz. 1∞ for 360 feet rise, and the decreasing humidity with height agree very well with later observations. Jeffries and Blanchard undertook a more perilous voyage on January 7, 1785, from Dover across the Channel, landing in the province of Artois, after, so runs the announcement, "we were suspended and floating in the atmosphere two hours over the sea and forty-seven minutes over the land of France." The voyagers were cordially welcomed, and were entertained lavishly in Paris as being, Jeffries says, "the first who passed across the sea from England into France by the route of the air." No instruments but a barometer and a compass were carried, and the only scientific result worthy of notice was that the balloon seemed to lose buoyancy over the sea, due to what Jeffries thought might be "the power of attraction over the water." The height of the balloon was measured trigonometrically by French officers in Calais, who found by angular measures, when the balloon was midway across the Channel, that its height was 4500 feet. Jeffries' voyages have been described somewhat at length because the first scientific balloon voyage is generally attributed to the Belgian physicist, Robertson, who ascended from Hamburg in 1803 to the improbable height of 24,000 feet. Robertson made his third ascent the next year from St. Petersburg, accompanied by the Academician Sacharoff. This was a scientific voyage, instituted at the request of the Russian Academy, to ascertain the physical state of the atmosphere and the component parts of it at different heights, also the difference between the results of vertical ascents and the observations of Deluc, De Saussure, von Humboldt and others on mountains, which it was rightly concluded could not be so free from terrestrial influences as those made in the open air. Among the experiments which the Academy proposed were the following: change of rate of evaporation of fluids, decrease