What Is This? It Is An Instrument To Design Silks

I found these swatches on my tours of the mills this year. These swatches are used by silk designers to work out the colour palette that will be used in designing the silks. When the textiles designers are working to create the silks they have loose versions of these which they plonk side by side to interpret the design. The silks are coded according to their colour and to confirm with the client what kind of look they are going for with their submitted designs. The example below came from France and was framed in glass. No doubt it would have come from the Lyonnaise silk mills and by the look of it I assumed it was over 100 years old.