“…Speculation seems to have replaced research, at least in the past. Brown and Hauser (9) listed the types of linkages then believed possible, and Van Amerongen and Houvink (84) considered each of them from the standpoint of steric stability and bond strains, with the conclusion that seven were theoretically possible,-two intramolecular and five intermolecular. XX would be formed by addition of hydrogen sulfide to a double bond, as advocated by Fisher (23), who thought that all vulcanization was caused by hydrogen sulfide generated by sulfurization of rubber or non-rubber hydrocarbon.…”