354 THE MATHEMATICAL PRINCIPLES [BOOK Jl they were descending. And by these motions the times of their falling were prolonged, and increased by half a second sometimes, and sometimes by a whole second. The second and fourth bladder fell most directly the first time, and the first and third the second time. The fifth bladder was wrinkled, and by its wrinkles was a little retarded. I found their diame ters by their circumferences measured with a very fine thread wound about them twice. In the following table I have compared the experiments with the theory ; making the density of air to be to the density of rain-water as 1 to 860, and computing the spaces which by the theory the globes ought to describe in falling. The weight of tlie bla !The diameters Che times ol falling from a height oi The spaces winch by the theory ought to have been described The difference be tween the theory and the experi ' •272 t, t-t in those times ments 128 grains 5.28 inches 19" 271 feet 11 in. — 0 it. 1 in. 156 5.19 17 272 0£ -f o 04 137* 5.3 18 272 7 -f 0 7 97d 5.26 22 277 4 + 5 4 99& 5 21