P. d’Allabille can barely contain his enthusiasm for a de Vivie four speed transmission made up of four sets of chainwheels and sprockets. While the sizes on the chainwheels and sprockets differ from set to set, the total number of teeth on each set is the same. The same length of chain can then be run across all four sets. Two sets of chainwheels and sprockets are mounted on each side of the bicycle. To allow rapid gear changes the chain is fitted with one of Paul de Vivie’s special ‘quick links’ (if you can call stopping and manually moving the chain to a different set ‘rapid’).
I like the footnote “Hum Hum !!”.
(Source gallica.bnf.fr/ Bibliothèque nationale de France)