xlviii Contents 



PAGE 



No. 23. VOLCANOES AND EARTHQUAKES. [From Nature, 



August i, 1872, Vol. vi. pp. 260, 261] . . .3 {<> 



The purpose of this paper is to give a reason why 

 a sudden volcanic eruption may frequently be accom- 

 panied by earthquake shocks, and how earthquakes 

 may occur without contemporaneous outbreaks . . 346 



Bischof's method of taking the phenomena ob- 

 served in the laboratory as a guide in physical geology. 



The practice of making reactions in sealed tubes is 

 considered. 



The accidents incident to it throw light on seismic 

 and volcanic phenomena . . . . . -347 



Suddenly opening a sealed tube may cause its ex- 

 plosion ; and the sudden relief of pressure by a volcanic 

 outburst may cause an earthquake .... 348 



Unexpected confirmation afforded a few months 

 later by direct experiment made on board the " Chal- 

 lenger." 



No. 24. ON A REMARKABLE EFFECT PRODUCED BY THE MO- 

 MENTARY RELIEF OF GREAT PRESSURE. [From Proc. 

 Roy. Soc. 1903, Vol. LXXII. pp. 88-92] . . 349 



The brass tube and the copper sphere which showed 

 the effect of sudden relief of great pressure were ex- 

 hibited at the meeting of the Royal Society when the 

 paper was read. 



The original experiment was made in the "Chal- 

 lenger" on 27th March, 1873, the day after she made 

 her deepest sounding in the Atlantic, when the bulbs 

 of both the thermometers used were crushed by the 

 pressure. 



The purpose of the experiment was to obtain ex- 

 perimental data for the use of the thermometer maker, 

 but the circumstances attending the experiment, and the 

 results obtained, were of the highest scientific interest. 



Description of the general arrangement of the ex- 

 periment and of the sealed tubes used .... 349 



Appearance of the metal tube and of the remains 

 of the glass tubes after being sent to a depth of 2800 

 fathoms 350 



Description of similar experiments made in the 

 Prince of Monaco's yacht, "Princesse Alice," in 1902. 



The experiment in the brass tube was a duplicate 

 of that made in the "Challenger." 



