1903.] produced ly the Momentary Relief of Great Pressure. 89 



other work, nothing was done until near the end of the cruise. The 

 brass tube (figs. 1 and *2, Plate 1) above referred to, was the case for 

 holding a piezometer which was accidentally broken. With it I 

 repeated the experiment which I had made in the " Challenger," with 

 this difference, that I used only one sealed glass tube. It was an 

 ordinary pipette of 50 c.c., sealed up at both ends close to the body. 

 It was wrapped in a piece of muslin and loosely packed with cotton 

 waste so as to occupy the middle of the brass tube. 



The length of the brass tube was 33 cm., and its diameter 4*13 cm. 

 Its weight without the cover was 350 grammes. Both the top and the 

 bottom are pierced with many holes so as to allow passage to the 

 water. 



Thus charged, it descended on the sounding line to a depth of 

 3000 metres, and when it came up it was evident from its appearance 

 that the experiment had succeeded. As in the experiment on board 

 the *' Challenger," the glass tube had been converted into a snow- 

 white powder. The external effect also was confined entirely to that 

 part of the brass tube which had been occupied by the sealed glass 

 tube. Above and below it there was no disfiguration. 



The copper ball (figs. 3 and 4, Plate 2) is an ordinary 5-inch ball for the 

 supply tap of a cistern. A spherical glass fractionating flask, having 

 a diameter rather less than 1J inch, was hermetically sealed close to 

 the spherical body. It was then wrapped in a piece of muslin, and 

 with loose packing of cotton waste it was enclosed between the two 

 copper hemispheres, which were then soldered together. The holes at 

 the poles of the copper sphere gave free communication with the sea 

 water. The copper ball was then attached to the dredging cable, 

 which took it to a depth of 3000 metres. When it came up no 

 external effect was visible. I could not believe that even a small 

 flask of the kind could support a pressure of 300 atmospheres, 

 and I concluded that it had collapsed shortly after leaving the surface. 

 Still, as the line was going to make a second excursion, and this 

 time to 6000 metres, I re-attached the ball along with a larger one 

 to it. 



On returning to the surface the ball had the appearance which you 

 see. If the soldered welt represent the equator, it will be seen that 

 both polar areas are as they were. Perpendicularly to the equator 

 a system of folds or creases runs northwards and southwards and 

 extends very little beyond the tropics. The creasing is most 

 accentuated at a part of the equator where there is a slight flattening. 

 It is evident that the glass flask when it collapsed was relatively near 

 this part of the ball. I did not open the ball, as I thought it would 

 be more instructive to keep it as it is. The debris of the glass flask 

 with the cotton waste is still inside it. 



The effect of the sudden relief of pressure on the copper ball is 



