The book “Parralèle de l’architecture antique avec la moderne”, 1766, is part of the ETH Rare Books collection and I was able to look at it in the archive of ETH. It was a little smaller than I thought it would be, as one can see on the picture where I hold it. It’s about 22×10 cm and the cover was stiff, due to which I had to be very careful while scrolling through the pages. The cover is worn out and maybe out of wood or something else as hard. Material wise it was out of pergament. Inside of the cover there were some sort of decoration or abstract painting which color are faded. Other than that the pages themselves had a red edge.