It is to the celebrated English aeronaut, Mr. Green, that the substitution of carburetted hydrogen or street gas for hydrogen is due, and since his ascent in 1821 no other means of inflation have been used. A great many quite successful and a few unsuccessful ascents have been made for pleasure or profit. Mr. Green, in the _Nassau_ balloon, passed over to Nassau, a distance of five hundred miles, in eighteen hours. This exploit was the cause of the name being bestowed upon the balloon. The _Giant_ of M. Nadar was exhibited in England, and it was an enormous one, being an hundred feet high, and nearly as wide in the widest part. But even this machine was outdone by the Godard “Montgolfier” balloon, which was one hundred and seventeen feet high, and carried a stove. We give illustrations of these celebrated balloons, and will now pass on to the more scientific portion of the subject and the ascents of Mr. Glaisher and other aeronauts for the purpose of making meteorological observations, and the use of balloons for purposes of observation in war. It appears that the first ascent for scientific investigation was made in the year 1803. The aeronauts were Messrs. Robertson and Lhoest. They ascended from Hamburg and came down at Hanover, and made meantime several experiments with reference to the electrical condition of the atmosphere, its influence upon a magnetic needle, and some experiments with regard to acoustics and heat. The report was presented to the St. Petersburg Academy, and contains the result of their interesting observations. The travellers ascertained that at the elevation to which they attained,—viz., 25,500 feet,—the temperature was on that July day fifty degrees colder, falling to 19·6°, while on the earth the thermometer had shown 68°. They ascertained that glass and wax did not become electric when rubbed, that the Voltaic battery lost much of its power, that the oscillation of a “dipping needle” increased as they mounted into the air, while sound was certainly less easily transmitted at that elevation, and struck them as less powerful in tone. The heat experiment was not a success, owing to the breaking of the thermometer. They wished to find the temperature of boiling water at that elevation, but when the experiment was about to be made Robertson accidentally plunged the instrument _into the fire_ instead of into the water. So the question was not settled. The effect upon the aeronauts was a sensation of sleepiness, and two birds died. The muscular powers of the voyagers also appear to have been much affected, and similar sensations may be experienced by travellers on high mountains who find their breath very short and a disinclination to exertion oppress them.