Properties of Red Vulcanized Fibre. 211 



They were made into approximately rectangular prisms 

 and the lengths of the three edges measured with a metal 

 millimetre scale, the fractions of a millimetre being esti- 

 mated by eye. They were next weighed on a delicate 

 balance. They were now placed in a beaker of water and 

 allowed to remain in for one or more days, when they 

 were taken out, and after wiping with a cloth, re- 

 measured and weighed. It was soon seen, however, that 

 the specimens swelled most near the edges, making the 

 measurement of their three dimensions of little value for 

 the purpose of calculating the volume, and consequently 

 these measurements were given up and the volume deduced 

 by weighing in water as well as in air. The results obtained 

 for some of the specimens are given in the following 

 tables and diagrams. It will be seen that the two dimen- 

 sions in the plane of the sheets, called the length and 

 breadth, have only altered slightly, while the third dimen- 

 sion at right angles to the plane of the sheet has increased 

 by about 30 per cent. 



Further, the final volume of the specimens was consider- 

 ably less than the initial volume plus the volume of the 

 water absorbed. [It was assumed in the calculations that 

 the water was at the temperature of maximum density, the 

 correction for the actual temperature, approximately 16° C, 

 being quite immaterial as far as the nature of the 

 results go.] 



In order to ascertain if temperature had any influence on 

 the amount of water absorbed or on the change of volume, 

 a bath was maintained at a temperature of approximately 

 60° C, and two specimens were placed in it and readings 

 taken in a similar way to those for the specimens in the 

 water at room temperature. The effect of the higher 

 temperature was clearly to cause both the water to be 

 absorbed more rapidly and the final volume to be attained 

 more rapidly, the maximum amount of water absorbed as 

 well as the change of volume both being smaller. 



For the sake of comparison, observations were made at 

 room temperature on two specimens of wood, one American 

 bass and the other white deal. Here the changes of dimen- 

 sions were all small and, as far as the measurements show, 

 approximately of the same order as that for the two dimen- 

 sions in the plane of the fibre, while the volume of the water 

 absorbed was at least as large as in the case of the fibre, but 

 did not appear to have reached its maximum amount when 

 the observations were discontinued. 



