138 Mr. S. U. Pickering on the Densities 



His equation extends from 80'5 to 46*9 per cent, (the values 

 are given below in Table I., which is mainly a reproduction 

 of Prof. Pucker's Table I.), and my breaks occurred at 78, 



Table 1. 



p. 



(a+bx— cd*) 



xio 6 . 



ml(nx-\-n-x) 



xio 6 . 



/3-«. 



y- a - 



8-54 



11130 





+ 13 



+32 



79-48 



11354 





-46 



-55 



78-62 



11490 





+64 



+ 52 



77-11 



11659 



1 



-13 



-18 



74-98 



11764 



2 



4-13 



+27 



73-01 



11766 



3 



+ 2 







7106 



11703 



5 







-14 



69-10 



11594 



10 



4- 9 



- 4 



67-12 



11452 



17 



4- 2 



- 8 



65-51 



11319 



27 



+35 



+23 



64-50 



11229 



34 



-72 



+87 



63-08 



11097 



46 



+16 



- 6 



6101 



10893 



55 



+ 12 



-18 



58-94 



10681 



46 



- 4 



-29 



56-89 



10466 



30 



+ 30 



4-14 



54-89 



10251 



17 



- 7 



-18 



52-91 



10037 



10 



- 7 



-18 



50-91 



9817 



5 



+11 



+ 5 



48-91 



9596 



3 







+ 3 



46-94 



9379 



2 

 sity 



1 



+ 19 



Averap'f p.rrnr in Hen 



12 



15 









72*8, 58, and 51 per cent., so that the calculations extend 

 but 2'5 per cent, beyond the first of these breaks *, a distance 

 wholly insufficient to disprove anything about a break the 

 position of which can be determined only with " extreme 

 difficulty to within 1 or even 2 percent." (Chem. Soc. Trans. 

 1890, p. 126). In the same way little can be concluded as to 

 the break at 51 per cent., for although the calculations extend 

 4 per cent, beyond it, they embrace only 2 experimental points 

 in this length |. That the calculations do not really bridge 

 over these two breaks to any appreciable extent, is clearly shown 

 by the fact that on extending them for any distance bevond 

 the points taken they at once begin to leave the experimental 

 values. I, therefore, must take the most decided exception 

 to Prof. Pucker's statement that his one curve can act as a 



* In some cases the position given for this break was as high as 79 per 

 cent , or only 1-5 per cent, from the end of Prof. Rucker's curve. 



t In some cases the position given for this break was as low as 49 per 

 cent., or 2 per cent, from the end of Prof. Rucker's curve. The mean 

 position was 49'9 per cent. 



