32 



THE VOYAGE OF H.M.S. CHALLENGER. 



succession. A single 



page of my laboratory book, taken at random, sufficiently 

 illustrates this. To avoid confusion, I give the records of two of the ordinary instru- 

 ments (with fresh water) alone, leaving out the records of those with sea-water, and I 

 insert [in brackets] the pressures and the average apparent compressibilities calculated 

 from the data. The water employed was that of the ordinary supply of Edinburgh, 

 and was boiled, for a short time only, to expel air : — 



II. 



jil 



IV. 



VI. 



2 c. 



28-0 



28-0 



56-0 



560 



85-0 



85-0 



136-2 



[Pressure 0-983 tons] 

 [4333] 



The left-hand column gives the readings of the external gauge, the next those of 

 Amagat's gauge, before, during, and after the application of pressure. The third gives 

 the pressure as read by one of the internal gauges described in my previous Report. 

 The fourth column gives the readings of the two piezometers selected ; the fifth the 

 pressure (in tons) for each experiment, and the compressibility calculated. The latter 

 numbers are multiplied by 10 8 . 



