Hemdé was a French trademark of photography development accessories and stereoscopes in the early 20th century. The name was composed of the location Hem (near Lille) and two letters of the surname of founder Maurice Delécaille[1].
Delécaille started from c.1902 with manufacturing accessories for development of photographic negatives[1]. He patented in 1907 a mechanism for a multiple view stereoscope, together with Émile Cuny and Paul Sorel[2].
Sorel joined as the second director to the Société Delécaille et Sorel and he continued the company independently from 1910[3]. He moved the business activities to Rue Nationale 89 in Lille[4] and both names Hemdé and Sorel appeared on the products.

Sorel died on 3 February 1913 at the age of 36[5]. The company was split and the manufacturing of the Hemdé products was continued by his widow. She moved to Rue Macquart 9 in Lille[6].
During the First World War, Lille was occupied by the German army on 13 October 1914. Four years of occupation followed, which took a heavy toll on the city and its inhabitants. It’s unlikely that the company could continue manufacturing and selling Hemdé products. Some companies were robbed of their machinery and raw materials for the benefit of the German war effort[7].
Lille was liberated on 17 October 1918. An advertisement from 1919 shows that the company survived the war and the business activities were resumed at Rue Macquart 3[8].
Stéréoscope-classeur Hemdé
The catalog from April 1914[9] shows a small collection of stereoscopes. The company only manufactured multiple view stereoscopes for glass stereoviews that were based on their patented mechanism. The devices were divided into three series:
Série I was intended for the 45 x 107mm stereoview format and featured a wooden cabinet for storing up to 300 glass slides.
Série II models were available for the formats 6 x 13cm, 7 x 15cm, 9 x 14cm, 10 x 15cm and 8,5 x 17cm. It also included a cabinet for up to 200 glass slides. The support for the formats 7 x 15cm, 9 x 14cm, 10 x 15cm is remarkable, because these were rare stereo formats.
Série III was available for all supported formats, but lacked a cabinet.

Mechanism and functions
The catalog contains a detailed description of the mechanism and a user manual. It mentions about the telescope:[9]
High precision instrument, with a simple and irreproachable mechanism, it has all the improvements of its counterparts in addition to serious advantages. It is distinguished from other similar devices as much by its extreme simplicity as by the robustness of its parts and its absolutely unbreakable mechanism which is protected from dust and humidity.
The Hemdé stereoscopes have a crank-driven bidirectional mechanism. Turning the crank lifts a slide from the tray and brings it in viewing position. Turning further will place the slide back in the tray and moves the tray over a rail to select the next slide. By depressing the indication knob, the slide tray can be moved freely back and forth to select a specific slide. A numbered index is visible bellow the knob.

The slide trays are made of wood and can contain 24 slides. Special trays for thicker autochromes were available and can contain 12 slides[10].
The lenses of the stereoscope can be focussed and the distance between the lenses is adjustable. Eyepiece blinders block incident light.
References
- Hemdé, L’Information photographique, January 1902, p.81 – via gallica.bnf.fr
- Cuny, Émile; Sorel, Paul; Delécaille, Maurice. Vis perfectionnée n° FR380115, 22 July 1907 – via data.inpi.fr
- Dissolution Soc. Delécaille et Sorel, Archives commerciales de la France, 16 February 1910, p.316 – via gallica.bnf.fr
- Changement d’adresses, L’Information photographique, January 1913, p.175 – via gallica.bnf.fr
- Décès du 3 février, Le Grand écho du Nord de la France, 5 February 1913 – via gallica.bnf.fr
- Ventes des fonds, L’Information photographique, January 1913, p.210 – via gallica.bnf.fr
- German occupation of north-east France during World War I – via en.wikipedia.org
- Les Stéréos Classeurs “Hemdé”, Le Grand écho du Nord de la France, 31 August 1919 – via gallica.bnf.fr
- Notice et prix courants des stéréoscopes classeurs “Hemdé”, M.P. Sorel, April 1914
- Hemdé slide tray for twelve 6x13cm autochromes, Collection André Ruiter, object number 192
See also: blogposts about Hemdé