466 



Dr. Carl Bams on the Absorption of 



/3-values are usually attached to the compressibility-curves for 

 orientation. 



Calling the two capillary tubes formerly used (preceding 

 paper, 1. c.) Nos. 1 and 2, their dimensional constants before 

 and after corrosion were as follows : — 



No. 1 



No. 2 



Internal diameter 

 (centim.). 



Section. 



Cold thread- 

 length. 



18-4 em. at 28° 

 14-0 cm. at 24° 



Original. 



Corroded. 



Original. 1 Corroded. 



•043 



■<m 



•052 

 •034 



•0015 -0021 



•0014 -0023 



| 



In these cases the temperature of the vapour-bath was but 

 1 85°, and the corrosion did not outrun the opaque stage. Seen 

 under the microscope, the solid water-glass nearly filled the 

 bore, being an opalescent warty accretion. The chart (p. 470) 

 contains the results for decrement of length of thread and of 

 compressibility so far as observed, after constant temperature 

 had set in. In all these experiments /3 is thoroughly deter- 

 mined * from at least four measurements between 20 and 

 400 atm., the initial lengths of thread returning on removal 

 of pressure. 



In case of No. 1, time was not observed until after nearly 

 an hour's boiling. The short curves thus refer to the end of 

 the experiments. The general conclusions are stated in the 

 preceding paper. 



4. The first of the new tubes to be heated was No. 3, with 

 the following constants : — 



Temperature of Vapour-hath, 185°. 



Internal diameter (cm.). 

 Original -0295 



Corroded 



•041; 



Section. 

 •00068 



•00135 



Cold thread-length 

 17-4 cm. at 23°. 



External diameter 

 about "3 cm. 



The observations with this tube were not satisfactory ; 

 possibly the temperature of the vapour-bath was insufficiently 

 constant ; possibly the clear stage of reaction is not reached 

 at 185° (cf. §12). The tube turned opaque and so remained. 

 The fouled meniscus was frequently lost, or could not be 



* Cf. Am. Journ. Sci. xli. p. 110 (1891). 



