SPECIFIC GRAVITY AND DISPLACEMENT OF SOME SALINE SOLUTIONS. 57 



havino; the value of 0*1 gram each, were taken, and after the ninth observation the 

 thermometer was taken out of the distilled water and dried ; the hydrometer was 

 removed from the experimental solution and put into the cylinder containing the 

 distilled water, and the temperature of the experimental solution observed by immersing 

 the thermometer and gently stirring the solution. 



The hydrometer was then dried and replaced in its case. 



To complete the experimental data, the air temperature and time of completion of 

 the experiment were noted. 



The following is the record of the experiment : — 



Y^ gram-molecule solution K . 



Hydrometer 17. 

 A.ir temperature . . = 19 '20° C. 



Initial solution temperature = 19'50° C. 

 Time . . . . =11.3 a.m. 



Added "Weight. 

 r32 grams. 





Reading. 

 5*2 millimetres. 



1*42 „ 





16-3 



>> 



1-52 „ 





27-5 



j> 



1-62 „ 





38-4 



>> 



1-72 „ 





49-4 



)> 



1-82 „ 





59-2 



)> 



1-92 „ 





70-1 



)> 



2-02 „ 





82-1 



5> 



2-12 „ 





93-0 



)) 



Mean added weight 



. 



= 172 gram. 



Mean reading 



. 



. 



= 49*02 millimetres 



Air temperature 



. 



= 19-30° C. 



Final solution 



temperature 



= 19-50° C. 



Time 



. 





= 11.16 a.m. 



It will be seen that the air temperature rose 0-1° C. during the experiment, 

 which occupied 1 3 minutes, and the solution temperature remained constant ; so the 

 bunsen in the fume chest was lowered to a further extent, and then preparations 

 for the next experiment, conducted in precisely the same manner with hydrometer 

 No. 3, were made. 



As this section deals only with temperature conditions, the following table has been 

 drawn up to show the temperature conditions which prevailed during the experiments 

 which were made on the -^^ and ^ gram-molecule solution of the potassium salt of 

 the mixed halides (chloride and iodide), these being the two solutions experimented 

 upon during the day : — 



TRANS. ROY. SOC. EDIN., VOL. XLIX., PART I. (NO. 1). 8 



