Inevitably, this considerable collection, which was entrusted to the care of librarians appointed on an ad hoc basis, could not take pride in its most magnificent pieces for long. Dampness, dust and rodents also took their toll, destroying much of what had not already fallen victim to vandalism and indifference. And so it happened that the municipal library which had been founded in 1803 was reduced to a mere 25,000 volumes by the time it officially opened its doors to eager readers eight years later (in November, 1811).

Throughout the entire 19th century, however, the collections grew, partly through purchases but particularly by means of gifts presented by the State or of bequests, some of which were very substantial. As a result, the original stock had doubled in size by 1880. A special place of honour among the most generous benefactors is due to Baron Louis Numa de Salis, who presented the city with 124 manuscripts, some 20 incunabula, a collection of medieval parchment documents, as well as thousands of old prints, engravings and drawings.