This is a vintage black and white engraving depicting a large telescope mounted on a substantial, tower-like structure. The telescope itself is long and cylindrical, angled upwards and to the right. It's supported by a complex network of wooden beams and bracing, forming a scaffolding-like structure around it. The telescope and its support are built upon a tall, square-shaped stone or brick tower, which appears to be quite massive and imposing. At the base of the structure, there are several small figures of people, giving a sense of scale to the enormous telescope. The background shows a slightly hilly landscape with a cloudy sky. The style of the engraving is detailed and precise, typical of 19th-century scientific illustrations. The text at the bottom reads 'L'instrument monte. (Page 80.)' which translates to 'The mounted instrument. (Page 80.)'.