Page:The Prince of Abissinia - Johnson (1759) - 01.djvu/47

 different density of the matter through which we are to pass. You will be necessarily upborn by the air, if you can renew any impulse upon it, faster than the air can recede from the pressure."

"But the exercise of swiming, said the prince, is very laborious; the strongest limbs are soon wearied; I am afraid the art of flying will be yet more violent, and wings will be of no great use, unless we can fly further than we can swim."

"The labour of rising from the ground, said the artist, will be great, as we see it in the heavier domestick fowls; but, as we mount higher, the earth's attraction, and the body's gravity, will be gradually diminished, till we shall arrive at Rh