236 NEWTON S PRINCIPIA. 



The principal term in # is 115.678, 

 The second is 1.609, 



. . ar= 114.069, 

 and ft= .895. 



Hence the space which the globe falling in water de 

 scribes is, by 



theory 11 3. 1741 



experiment- 112. j 



Experiment 3. Three equal globes, whose weights were 

 severally 121 grains in air and 1 grain in water, were suc 

 cessively let fall, and they fell in water through a 

 height of 112 inches in the times 46&quot;, 47&quot;, and 50&quot;. 

 By theory these globes ought to have fallen in about 40&quot;. 

 The weight of the globe in water is so small, that any 

 errors in the weighing, or produced by the rarefaction of 

 the wax, by the heat of the hand, or by the weather, or 

 by bubbles of air adhering to the globes, become sensible. 

 That the experiment may be certain, the weight of the 

 globe in water should be several grains. 



Newton began the foregoing experiments to investigate 

 the resistances of fluids, before he had discovered the 

 theory laid down in the preceding sections. In order to 

 examine the theory after its discovery, he undertook 

 another course of experiments. He procured a wooden 

 vessel, whose breadth on the inside was 8 inches and 

 depth 15 feet. He made four globes of wax with enclosed 

 lead, each weighing 139^ grains in air, and 7-| grains in 

 water. These he let fall, measuring the times of their 

 falling in the water with a pendulum oscillating half 

 seconds. The globes were cold, and had remained so for 

 some time, both when they were weighed and when they 

 were let fall, because warmth rarefies the wax, and by 

 rarefying it diminishes the weight of the globe in water, 



