Annotated photograph "29 June 1960" linked to hydrostatic transmission tests

In this document

This item is a sepia-toned black and white photograph p. 1. It shows a country road bordered on the right by a dense coniferous forest and on the left by a light-coloured embankment, perhaps snow-covered, with a telegraph pole on the roadside p. 1.

A car is driving, seen from the rear: dark bodywork, light-coloured canvas sunroof that appears to be open, rear window visible, and a round motif on the rear body whose nature (grille or emblem) remains uncertain p. 1.

Two handwritten annotations accompany the image: the mention in black ink "29. Juin 1960" at the top left, and the number "60" drawn in red and circled in an oval at the top right p. 1.

No element of the document explicitly describes or names a hydrostatic transmission: this item is associated with the title of the archive box, but its own content is limited to this annotated photograph.

Context

The title of the box from which this item originates evokes a "brief operating principle of a hydrostatic transmission adapted to a motor vehicle". Hydrostatic transmissions, which replace the classic mechanical linkage with a hydraulic circuit (hydraulic pump and motor), were the subject of research by several manufacturers in the late 1950s and 1960s, a period when Citroën, notably via Paul Magès, was exploring numerous applications of hydraulics to the automobile — beyond the hydropneumatic suspension already implemented on the DS.

The handwritten date "29 June 1960" places this photograph in the middle of the development period of these hydraulic researches at Citroën, without the document allowing for more precise details on the nature or context of the test.

Archivist's perspective

It is probable that this photograph documents a road test linked to research on hydrostatic transmissions, given its attachment to the box title, but nothing in the image itself — a vehicle driving on a country road — allows this to be stated with certainty p. 1.

The red number "60" surrounded by an oval suggests a numbering or archive classification, perhaps added a posteriori, whose precise meaning remains unspecified p. 1. This isolated item would benefit from being compared with other documents in the same box devoted to the principle of hydrostatic transmission to clarify its exact role in the file.