Changes of Curvature by Means of a Flexible Lath, 445 



Case II. 

 This is an instance of a break of a very uncertain character, 

 at any rate as to its position. The experimental results are 

 given in Table IV. : they consist of determinations of the 

 depression of the freezing-points of acetic acid by propyl 

 alcohol. The average mean experimental error is 0°*042 ; 

 but at three points it attains exceptionally large dimensions, 

 and when these three points are omitted we get o, 029 as 

 the mean error : when determined by a graphic method which 

 I have described in the Ber. d. deutseh. chem. Gesel. xxiv. 

 p. 3332, and xxv. p. 1100, 0°*027 was obtained as the mean 

 error; and I have taken the mean of these three numbers, 

 namely 0°*033, as the most probable value for it. 



Dep.p 

 0° A 



for 

 AB 



10° C 



Z 



for 

 EF 



10 



Fig. 1.— Per cent, of Propyl Alcohol (for AB and CD). 

 8 16 24 



32 



20° 





for 

 CD 



10° 



2-5 5- 7-5 



Mols. Sugar to 100 H 2 (for EF). 



10 



On examination of the figure it appeared to consist of a 

 curve followed by a straight line, the break being at about 

 Phil. Mag. S. 5. Vol. 33. No. 204. May 1892. 2 H 



