172 



MR J. Y. BUCHANAN ON THE 



§ 90. Table of Specijic Gravities calculated from Single Observations made with 

 Hydrometers A and B when floating hi a Solution of Calcium Chloride con- 

 taining 6*3 gram-molec\des in 1000 grams of Water. 







Hydrometer A. 



Added 

 Weight in 

 Grams for 



Hydro- 

 meter B. 



Hydrometer B. 



Added 

 Weight in 

 Grams for 



Hydro- 

 meter A. 



Series 1. 



Series 2. 



Series 3. 



Series 1. 



Series 2. 



Scale 



Reading 



in 



Milli- 

 metres. 



Specific 

 Gravity 

 calculated 

 from Single 

 Observa- 

 tions. 



Scale 



Reading 



in 



Milli- 

 metres. 



Specific 

 Gravity 

 calculated 

 from Single 

 Observa- 

 tions. 



Scale 



Reading 



in 



Milli- 

 metres. 



Specific 



Gravity 

 calculated 

 from Single 



Observa- 

 tions. 



Scale 



Reading 



in 



Milli- 

 metres. 



Specific 



Gravity 

 calculated 

 from Single 

 Observa- 

 tions. 



Scale 



Reading 



in 



Milli- 

 metres. 



Specific 

 Gravity 

 calculated 

 from Single 

 Observa- 

 tions 



4-0 

 4-1 

 4-2 

 4-3 

 4-4 

 4-5 

 4-6 

 4-7 

 4-8 

 4-9 

 5-0 



13-9 

 21-8 

 29-6 

 37-2 

 44-6 

 52-2 

 59-8 

 67-1 

 74-7 

 82-2 

 89-7 



1-409760 

 735 

 731 

 730 

 744 

 749 

 762 

 776 

 764 

 762 

 761 



141 



21-7 

 29-7 

 37-2 

 44-9 

 52-1 

 59-8 

 67-2 

 74-9 

 82-4 

 89-9 



1-409741 

 745 



722 

 730 

 722 

 765 

 768 

 772 

 750 

 748 

 747 



14-0 



21-5 

 29-5 

 37-4 

 44-8 

 52-1 

 60-1 

 67-5 

 74-8 

 82-6 

 89-7 



1-409750 

 764 

 741 

 711 

 731 

 765 

 741 

 744 

 760 

 730 

 767 



2-05 

 2-15 

 2-25 

 2-35 

 2-45 

 2-55 

 2-65 

 2-75 

 2-85 

 2-95 

 3-05 



7-1 

 15-9 

 24-5 

 33-5 

 42-8 

 50-8 

 60-0 

 67-9 

 77-8 

 86-0 

 94-8 



1-409740 

 732 

 744 

 725 

 683 

 751 

 723 

 725 

 694 

 740 

 739 



7-0 

 15-8 

 24-7 

 33-8 

 42-0 

 50-9 

 59-0 

 68-1 

 76-9 

 86-0 

 94-8 



1-409750 

 742 

 724 

 696 

 760 

 742 

 818 

 790 

 782 

 740 

 739 



Mean Specific 

 Gravity. 



§ 



1-409752 





1-409746 





1-409746 







1-409727 





1-409753 



Probable 

 error, ex- 

 pressed 

 in units 

 of the 6th 

 decimal 

 place 



of a single 

 observation 

 ±r. 



10-3 





11-6 





11-9 





14-8 





20-1 



of the arith- 

 metical 

 mean +?'q. 



31 





3-5 





3-6 







4-5 





6-4 



The hydrometer A, constructed on the above specification, has proved itself, in use, 

 to be an excellent model. Its volume, about 137 c.c, is very suitable, being sufficiently 

 great to secure precision without rendering it necessary to use extravagant quantities 

 of very soluble salts, which, in the case of costly preparations, might be prohibitive. 

 It is very steady, and this is principally due to the fact that the ballast is all contained 

 in the bulb at the lower extremity. The position of the centre of gravity of the 

 instrument is thus kept very low, and in the spherical bulb the ballast cannot shift. 



Section XIII. — On the Specific Gravity and Displacement of Solutions of 

 Salts of the Ennead MR which have nearly the same Molecular 

 Weight and may be looked on as "Isomeric." 



§ 91. There are three such groups of salts in the ennead, namely, KBr and RbCl ; 

 KI, RbBr, and CsCl ; and Rbl and CsBr. Experiments have been made on strong 

 solutions of the first group, KBr and RbCl. To these " natural isomers " we have added 



