38 



NEW METHOD FOR DETERMINING COMPRESSIBILITY 



1S.725 grams (corrected to vacuum) respectively. The weight of the 

 thin bulb in series 19 was 1.09 grams of course none was used in 

 Series 20 and 21. 



These figures are plotted as usual on the diagram (Fig. ^), and yield 

 a curve of the same type as the others, with very few discrepant points. 

 The highest results of each series falls exactly upon the curve, showing 

 that the methods give identical results within the necessary limits of 

 error of each. Hence the thin glass bulb used in Series 19, as well as 

 earlier in Series 1 to 13, introduced no appreciable error. It is worthy 

 of note also that the compressibility of a saturated solution of iodine in 

 water may be computed from the experiments on iodine, and is found 

 thus to be less than one per cent, different from that of pure water 

 at each point in the curve. The small magnitude of this difference 

 confirms both the work and the calculation of the iodine results. 



From the curve given on the diagram the compressibility of pure 

 water may be found as follows : 



Compressibility of Water. 



Thus water is between eleven and twelve times as compressible as 

 mercury, and about half as compressible as chloroform. 



Other experimenters have rarely used 20 as their standard tempera- 

 ture, hence their results must be reduced before comparison with ours. 

 Several investigators have shown that the compressibility of water 



