28 



NEW METHOD FOR DETERMINING COMPRESSIBILITY 



to 0.2509 liter, and as an average of three closely agreeing titrations 

 17.32 milliliters of this solution required 45.45 milliliters of the thio- 

 sulphate solution. Therefore the number of grams of iodine in B was 

 4.7723 grams. The weights of the glass in the two bulbs A and B 

 were respectively 0.91 and 0.97 gram, and the weights of water pres- 

 ent in each were respectively 2.674 anc * 1-829 grams. 

 In both cases jacket II was used. 



Compressibility Data for Iodine. 

 Bulb A. 



Under m' is given the percentage change in volume of 2.674 g ram s 

 of water and 0.1643 g ram f iodine minus the percentage decrease of 

 an equal volume of mercury. (6) and (7) are two series, the first 

 made by adding small quantities of mercury, the second by taking- out 

 small quantities after the highest pressure had been reached. This 

 method of procedure is especially desirable with solids, as it will af- 

 ford indication of a permanent alteration in the volume of the solid 

 under pressure, if such alteration occurs. It also gives valuable proof 

 of the absence of leakage from the glass jacket. 



Under n' is given the percentage decrease in the volume of 1.829 

 grams of water and 4.7723 grams of iodine minus the percentage de- 

 crease of an equal volume of mercury. (8) and (9) are two series 

 made as before, one by adding mercury, the other by taking out small 

 quantities of mercury. By adding the compression of mercury, m and 

 n are respectively obtained from m' and n' . 



Making the calculation indicated in the earlier part of the remarks 

 on iodine, we have in the equation S = bc/a, by substituting the values 

 found, 

 <J = 0.1643 x l .829/2.674 = 0.1 124 gram and (d d) = 4.66 grams. 



