122 C. E. Linebarger — Apparatus for the Bapid, etc. 



It is at once apparent that only in several instances the dijffer- 

 ences between Ramsay and Shields' results and mine amount 

 to more than a few tenths of a per cent., and in some cases the 

 agreement is as good as perfect. Moreover, the differences 

 that are found are very nearly the same when either pair of 

 tubes is employed ; this indicates that the differences are due 

 to the possible differing degrees of purity in the liquids 

 employed by each of us rather than to a fault in the apparatus 

 itself. However that may be, the data show that it is possible 

 to obtain with the apparatus results which, by means of the 

 formula (A), are comparable with those obtained by Ramsay 

 and Shields (loc. cit). One cannot withstand the temptation 

 to quote Jager's words (loc. cit.) " . . . . unsere Methode ist 

 vollstandig geeignet, richtige Resultate zu ergeben. Fasst 

 man noch die leichte, sichere und wenig Zeit beanspruchende 

 Handhabung, welche unser Apparat erfordert, ins Auge, so 

 wird man wohl leicht zur tJberzeugung gelangen, dass unter 

 den gegenwartigen Metboden fiir den praktischen Gebrauch 

 kaum eine besserezu finden sein diirfte." As to what pertains 

 to the experimental handling of the apparatus, my experience 

 with it permits me to subscribe to the above. But a restric- 

 tion has to be made in regard to the conversion of the indirect 

 results furnished by it into direct ones. Jager's formula has 

 been shown above to be only approximately correct, and the 

 one which I propose has but an empirical basis. Although it 

 has been found to stand the test of comparison with ten 

 liquids of different properties, when two sets of tubes were 

 employed, it is not allowable to claim that it will furnish 

 accurate results for any liquid whatsoever. In other words, 

 the instrument cannot be depended upon to give absolute data, 

 as the " apparatus constant " may differ from liquid to liquid. 

 Still its usefulness is but slightly impaired by that circum- 

 stance. There is a vast amount of work to be done in the field 

 of solutions, in which the method can yield excellent results. 

 Here the measurements can be considered to be more correct, 

 since in work with solutions the "apparatus constant" can be 

 determined specially for the solvent. Among some of the 

 problems that may be investigated by means of the method, 

 mention may be made of the following : the superficial ten- 

 sions of saturated solutions in contact with the solid substance 

 can be very well determined even when the solutions are quite 

 concentrated, and it is likely that a knowledge of this property 

 of solutions will enable us to get at the molecular masses of 

 solids : also, the molecular masses of liquids can be determined 

 very rapidly by the method. 



The apparatus described above was made by Walmsey, Ful- 

 ler and Co. of Chicago, and has proven satisfactory in every 

 particular ; the makers inform me that they can now furnish 

 the apparatus provided with a micrometer screw divided 

 according to the metric as well as English system. 



