Ton GnwaAr bvuuPs 109 
could throw Mount Everest into this ‘“‘ deep,” 
the mountain would be swallowed up, with 
2600 feet to spare. The ‘‘Swire deep,” off 
Mindanoa, is actually a little over 6 miles in 
depth. 
GREAT PRESSURE 
In deep water there is necessarily great 
pressure, because of the immense weight of 
water. At 2500 fathoms it is 2!% tons on the 
square inch—an unendurable pressure, if it 
were felt. It is twenty-five times greater than 
the pressure exerted by the steam on the pis- 
ton of our best railway locomotives. The 
general reason why the pressure is not felt is 
that the bodies and tissues of the animals are 
permeated by the water. If a ship’s hawser 
is sunk to a great depth, it is squeezed to less 
than the diameter of one’s wrist. If a piece 
of wood is weighted and sunk to a great 
depth, it is so much compressed that it will 
no longer float when brought to the sur- 
face again. But if a delicate glass vessel with 
holes all over be lowered it is not broken, for 
the water goes through and through it. Ina 
general way, this is true of the deep-sea ani- 
mals. But this is not the whole truth. 
