Between about 1914 and this 1930 leaflet remarkably little had changed in the world of Le Chemineau. The gear system is still based on a 3 speed freewheel, the derailleur looks identical, the lever is still mounted on the top tube of the Chemineau Ballon 1930 model shown - and then there is the, rarely hidden, overweening pride.
The logic goes; a bicycle needs to have gears, the best gears are derailleur gears, the best derailleur is Le Chemineau, the best derailleur bicycles are Chemineau bicycles, the Chemineau bicycle is made in St-Étienne using the best components, the best steels and elite workers - all probably true in 1914, but testing the bounds of credibility in 1930. The only missing ingredient is any trace of humility.
The various speed charts and tables of gradients are entertainingly odd.