214 Some Properties of Red Vulcanized Fibre. 



The first specimen of fibre immersed, after being in for 

 9 days, was taken out and found at the end of 9 days to have 

 yielded up 90 per cent, of its absorbed water. 



The explanation of the enormous change in one dimension 

 did not perhaps appear clear. In order to account for this 

 thin sections were examined under the microscope, when it 

 was seen that the structure was very heterogeneous. When 



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we attempt to split the fibre it yields easily in the plane of 

 the sheet with a more or less flaky appearance, but it is 

 very difficult to split in a direction perpendicular to the 

 sheet. This agrees with the character of the sections in 

 the plane of the sheet and perpendicular to it as seen in the 

 microscope. The sections in the plane of the sheet showed 

 a mass of long fibres or cells separated by a considerable 

 amount of matrix or intercellular space, while the sections 

 perpendicular to the sheet were of a very much denser 

 character and showed only a few fibres longitudinally. 

 (The sections perpendicular to the plane of the sheet were 

 also much harder to cut than those in the plane of the sheet.) 

 In the manufacture of the sheets great pressure is applied 

 when the walls of the fibres or cells are in a partly gelatinous 

 state, and hence the number of fibres or cells per centimetre 

 perpendicular to the plane of the sheet is immensely greater 

 than the number in the plane of the sheet, and consequently 

 when water is absorbed the amount of swelling perpendicular 

 to the plane of the sheet is much greater than in the plane- 

 of the sheet. 



