Of the increased coldness which you feel on passing from a bright cloud into a dark one, the balloon is quite as sensitive as you can be; and, probably, much more so, for it produces an immediate change of altitude. The expansion and contraction which romantic gentlemen fancied took place in the size of their heads, does really take place in the balloon, according as it passes from a cloud of one temperature into that of another. We are now nearly three miles high. Nothing is to be seen but pale air above--around--on all sides, with floating clouds beneath. How should you like to descend in a parachute?--to be dangled by a long line from the bottom of the car, and suddenly to be "let go," and to dip at once clean down through those gray-blue and softly rose-tinted clouds, skimming so gently beneath us? Not at all: oh, by no manner of means--thank you! Ah, you are thinking of the fate of poor Cocking, the enthusiast in parachutes, concerning whom, and his fatal "improvement," the public is satisfied that it knows every thing, from the one final fact--that he was killed. But there is something more than that in it, as we fancy. Two words against parachutes. In the first place, there is no use to which, at present, they can be applied; and, in the second, they are so unsafe as to be likely, in all cases, to cost a life for each descent. In the concise words of Mr. Green, we should say--"the best parachute is a balloon; the others are bad things to have to deal with." Mr. Cocking, as we have said, was an enthusiast in parachutes. He felt sure he had discovered a new, and the true, principle. All parachutes, before his day, had been constructed to descend in a concave form, like that of an open umbrella; the consequence of which was, that the parachute descended with a violent swinging from side to side, which sometimes threw the man in the basket in almost a horizontal position. Mr. Cocking conceived that the converse form; viz., an inverted cone (of large dimensions), would remedy this evil; and becoming convinced, we suppose, by some private experiments with models, he agreed to descend on a certain day. The time was barely adequate to his construction of the parachute, and did not admit of such actual experiments with a sheep, or pig, or other animal, as prudence would naturally have suggested. Besides the want of time, however, Cocking equally wanted prudence; he felt sure of his new principle; this new form of parachute was the hobby of his life, and up he went on the appointed day (for what aeronaut shall dare to "disappoint the Public?")--dangling by a rope, fifty feet long, from the bottom of the car of Mr. Green's great Nassau Balloon.