Magnificent French alidade, which was probably used during the I World War. Alidades are devices designed to calculate the shooting angle of canyons. They were put on these weapons to get the precise angle to shoot. This particular instrument is made of polished brass, very shiny, and comes into its original wooden case. The box, with sliding cover, is somewhat worn but can be easily restored by a professional. The metal is in good condition, and the alidade (a circular scale for measuring angles) also looks good. It is made of silvery metal and by its side stands part of a white plate, fixed by two screws. On the parallel base/rule of the alidade we can see the name of the brand engraved in the metal. The name, Chasselon Cachan, appears into a triangle which is surrounded by a circle, making an elegant logo. Chasselon Cachan was a French brand which made optical surveying instruments, such as alidades or theodolites. Apart from the logo and name of the brand, if we turn the instrument upside down we will find an engraved inscription: CAD 1953_23. The alidade keeps all its original parts. The lenses are perfect and the instrument is in good condition, working as new. The length of the base (more than fifty centimeters) stands out, providing stability and elegance. The screws turn smoothly and let the user operate the device quite easily. Some metal parts are slightly worn, which is logical if we consider the age of the piece. The level located on the base is in perfect condition, keeping the original bubble and the glass, which has a red circle painted in the center. Overall, this is a fine surveying instrument that was probably used in a historical war, a fact that turns it into a first-class war antique, worthy of the best collections. Measurements: 510 mm lenght x 110 mm height.