the mud solidifies, and becomes rock in a thousand years. The soft 

 layer should not be more than about a yard thick. Other scientists 

 estimate that the thickness of the yearly sedimentary deposit is not 

 even as great. Down where we were, south of Capri, far from a river 

 mouth, I expected only a very slight deposit. Now what did we see ? 

 Nothing! The cabin was stuck in the mud up to the porthole. (Upon 

 our return, examining it, my son worked out that it liad gone 4 ft. 6 in. 

 deep into the mud.) 



During the descent we had been rejoiced to think of the discoveries 

 that we should make, once on the bottom. And we saw nothing. The 

 light from the projectors did not reach us: when we turned on the 

 interior lighting we saw that a sandy mass was obstructing the window. 

 In fact the samples of soil which remained stuck to the cabin showed 

 that it was not sand but a substance of very fine composition, almost 

 dusty, which to the naked eye appeared homogeneous : this explained 

 why we entered it so easily. The Institute of Applied Geology at 

 Milan asked us for a sample, so we sent them some. The macrophoto- 

 graph of it showed its composition. It is in masses of this formation 

 that, in the course of millions of years, oil is formed. 



This time no observations were possible. During the dive on the 

 14th August, 22 fathoms down, we had seen the bottom perfectly: 

 the descent had been slow and the Trieste had not driven into the mud. 

 The same thing had to be achieved also at great depths. (A balloonist 

 must make six ascents before he obtains his pilot's licence and on 

 several occasions the instructor goes with him; the pupil aeroplane 

 pilot must fly as an onlooker with his teacher before being allowed to 

 fly in dual control, then to be at the controls alone, and lastly to be 

 left to himself. It was quite otherwise for the pilot of the bathyscaphe.) 



The aim of today's dive was to prove the strength of the bathy- 

 scaphe, and the objective had been attained. But even in these condi- 

 tions the cabin could already render great services as a laboratory, 

 particularly for the measurement of gravitation. The geophysicists 

 have installed a network of stations over the globe. In these they 

 proceed to the measurement of ground acceleration : the data gathered 

 allows the geological structure of our planet to be studied. For this the 

 observatory has to be safe from any vibration or movement: ships 

 therefore cannot be used. Now, to know the gravitation between the 

 continents would be of the highest importance: the information 

 gathered would permit us to determine the structure of the part of the 



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