theory of permeability / further speculation
*
Fig. 4. — Section of balloon fabric, showing crystals of sulphur. (x138)
(cropped from page)
ex Junius David Edwards and S. F. Pickering. "Permeability of Rubber to Gases." Scientific Papers of the Bureau of Standards 16 (1921) : 327-362
University of Chicago copy, digitized May 24, 2012
The free sulphur which is present in the colloidal condition in the rubber after vulcanization frequently crystallizes out... Fig. 4. The sulphur crystals are seen as dark dendritic masses in the rubber between the two plies of cloth. A certain amount of this sulphur eventually penetrates to the surface and evaporates. This process might possibly produce a certain porosity which would increase the permeability. [But] tests... showed no significant difference in permeability as compared with portions where crystallization had not occurred...
(p337)
epigram ex pp 360-361
12 January 2014
tags: J. D. Edwards; S. F. Pickering; lighter than air; speculative knowledge; vulcanization