SEC. V1L] OF NATUKAL PHILOSOPHY. 3-1 *J .reighed and when they were let fall ; because warmth rarefies the wax. and by rarefying it diminishes the weight of the globe in the water ; and wax, when rarefied, is not instantly reduced by cold to its former density. Be fore they were let fall, they were totally immersed under water, lest, by the weight of any part of them that might chance to be above the water, their descent should be accelerated in its beginning. Then, when after their immersion they were perfectly at rest, they were let go with the greatest care, that they might not receive any impulse from the hand that let them down. And they fell successively in the times of 47 J, 48^, 50, and 51 os cillations, describing a height of 15 feet and 2 inches. But the weather was now a little colder than when the globes were weighed, and therefore 1 repeated the experiment another day ; and then the globes fell in the times of 49, 49i, 50. and 53; and at a third trial in the times of 49£, 50, 51. and 53 oscillations. And by making the experiment several times over, I found that the globes fell mostly in the times of 49