As with the small ad from April 1900, this advert is for a Herstal bicycle fitted with a 4 speed transmission of some sort by Paul de Vivie. The gear ratios are (in French terms) 3.50m. 4.50m, 5.50m and 6.50m. In gear inches the equivalent numbers are: 44”, 56”, 69” and 81” respectively.
The ‘parc d’aérostation d’Itteville’ (‘Itteville airfield’) is an appropriate address for a dashing young consumer of innovative bicycles in 1901. Hopefully, he had a moustache that you could hang your coat on.
(Source gallica.bnf.fr/ Bibliothèque nationale de France)