MR J. Y. BUCHANAN ON THE 



SECTION X. 



Experimental Observations on the Displacement op Solutions of Sodium Chloride. 

 PAR. page 



67. Although sodium chloride is not a member of the enneads which form the principal material 148 



of this research, its importance in nature justifies its inclusion in it. General table of 

 results of experiments made on solutions of sodium chloride varying in concentration 

 from 1 gram-molecule to 1/512 gram-molecule per 1000 grams of water. 



68. Preparation of solutions forming arithmetic series. 149 



69. Tables giving results of solutions for which m forms a geometric series of the usual type. 150 



70. Discussion of specific gravity. 150 



71. Discussion of displacement. 150 



72. Experiments on solutions forming arithmetic series. 151 



73. Series of experiments on solutions having the common difference dm = 1/128. 151 



74. Discussion of differences of displacement. Table confirming the reality of the remarkable 151 



changes of displacement in high dilutions. 



75. Table giving further confirmation of this. 152 



76. Table giving series of experiments on solutions having the common difference of concentra- 153 



tion dm = 1/64. 



77. Discussion of displacement and differences of displacement. 153 



78. Diagram giving graphic representation of remarkable changes in the values of vjm at high 154 



dilution. 



SECTION XI. 

 The Principle and Construction of the Open Hydrometer. 



79. The hydrometer is left open so that its weight may be increased or reduced by additions 155 



to, or removals from, its ballast or internal load. The extent to which additions can 

 be made to the weight supported by the stem of the instrument is limited by its stability. 

 The Challenger hydrometer, which was closed, could be used in a saturated solution 

 of sodium chloride carrying an accessory weight of 32 grams. In a solution of greater 

 density, the external weight required produced a "list." 



80. The open hydrometer may be of the same size as the closed instrument, and is made after 155 



the ordinary pattern, but the millimetre scale is etched on the stem, the paper scale 

 being impossible when the internal load is to be varied. When concentrated solutions 

 of salts which are both very soluble and very expensive are used, it is convenient to 

 use a hydrometer of less bulk than that of the closed instrument. 



81-84. The weight of the instrument is not constant, because the internal ballast is altered from 157 



time to time, and the weight of the air in the hydrometer varies with the meteorological 

 conditions. The first step in the preparation of the hydrometer for use is to weigh the 

 glass instrument empty as it comes from the glass-blower. It is then weighed with 

 the ballast (lead shot) in it. Knowing the density of the glass and that of the lead, 

 we obtain the volumes of the glass and the lead respectively. When the instrument is 



