SUMMARY OF RESULTS. 



It is explained in the preceding pages that the pressures employed in the experiments 

 ranged from 150 to 450 atm., so that results given below for higher or lower pressures 

 ( and enclosed in scpiare brackets] are extrapolated. A similar remark applies to 

 temperature, the range experimentally treated for water and for sea-water being only 

 0° to 15° C. Also it has been stated that the recording indices are liable to be washed 

 down the tube, to a small extent, during the relief of pressure, so that the results given 

 are probably a little too small. 



Compressibility of Mercury, per atmosphere, . . . '0000036 



Glass, ..... 0-0000026 



Average compressibility of fresh water : — 



[At low pressures 520.10- r -355.10- 9 < + 3.10- 9 / 2 ] 



For 1 ton = 152-3 atm. 504 360 4 



2 „ =304-6 „ 490 365 5 



3 „ =456-9 „ 478 370 6 



The term independent of t (the compressibility at 0° C.) is of the form 



10- 7 (520- 17 yJ +i- 2 ), 

 where the unit of p is 152'3 atm. (one ton- weight per sq. in.). This must not be 

 extended in application much beyond p = 3, for there is no warrant, experimental or 

 other, for the minimum which it would give at p = 8 '5. 



The point of minimum compressibility of fresh water is probably about 60° C. at 

 atmospheric pressure, but is lowered by increase of pressure. 



As an approximation through the whole range of the experiments we have the 



formula : — 



0-00186 / _ 3l_ P \ 

 36+jA 400 + 10,000/; 



while the following formula exactly represents the average of all the experimental 



results at each temperature and pressure : — 



10" 7 (520 - 1 lp +2< 2 ) - 10" 9 (355 + op) t + 10" 9 (3 +p) f. 



Average compressibility of sea-water (about 0"92 of that of fresh water) : — 



[At low pressures 481. 10-- 340.10- 9 / 1 + 3.1Q-V] 



