20 THE FAUNA OF THE DEEP SEA 



placed it, so wrapped np, in a wide copper tube, 

 wliicli was one of those used to protect the deep-sea 

 thermometers when sent down with the sounding 

 apparatus. 



'This copper tube was closed by a lid fitting 

 loosely, and with holes in it, and the copper bottom 

 of the tube similarly had holes bored through it. 

 The water thus had free access to the interior of the 

 tube when it was lowered into the sea, and the tube 

 was necessarily constructed with that object in view, 

 in order that in its ordinary use the water should 

 freely reach the contained thermometer. 



' The copper case containing the sealed glass tube 

 was sent down to a depth of 2,000 fathoms and 

 drawn up again. It was then found that the copper 

 wall of the case was bulged and bent inwards 

 opposite the place where the glass tube lay, just as if 

 it had been crumpled inward by being violently 

 squeezed. 



' The glass tube itself, within its flannel wrapper, 

 was found when withdrawn, reduced to a fine powder, 

 like snow almost. What had happened was that the 

 sealed glass tube, when sinking to gradually increas- 

 ing depths, had held out long against the pressure, 

 but this at last had become too great for the glass 



