Replacement eyepiece for M2 respirator : French Army

Spare eyepiece for the French Army M-2 Respirator. The circular aluminium outer frame of the eyepiece has an inner surface with scalloped edges, while the outer has a cardboard ring to hold the window in place. The window is of yellow cellophane treated with an anti-dimming solution. The eyepiece was originally stored in a pocket inside the respirator carrying satchel REL31834.001.

The M-2 Mask was introduced into French Army service in March 1916, as a replacement for the enormous variety of inefficient 'pad' and helmet respirators which had been rushed into production following the first German use of poison gas in April 1915. These included the C-1, C-2, C-3, TNH and LTN, as well as the 'Detourbe', 'Piedalu' and 'Robert' masks. The M-2 consisted of a number of layers of muslin impregnated with absorbent chemicals, which wrapped around the face, and were protected from the elements by a weather-proof flap of oiled fabric. Typical makeup of the absorbent solutions was up to twenty layers of fabric impregnated with castor oil, alcohol, glycerine and sodium hydroxide (this compound known as 'Greasene') and a further twenty layers of 'Complexene', which was composed of hexamine, glycerine, nickel sulfate, sodium carbonate and water. Since there was no outlet valve, all air breathed had to pass both in and out through the impregnated fabric of the hot and stifling mask. This required considerable effort on the part of the wearer, and restricted physical exertion to a minimum. Despite these drawbacks, the M-2 was fairly comfortable to wear for extended periods, and could be expected to provide over an hour's protection from high concentrations of gas. It was the standard French infantryman's respirator for the bulk of the war, and was not replaced in service until the later part of 1918, when the ARS ('Appareil Respiratoire Special') mask, which was based upon the contemporary German 'lederschutzmaske', was introduced. Early M-2 masks featured a single rectangular cellulose or cellophane window over the eyes, but as this was subject to damage and impossible to remove or repair, it was replaced from April 1916 by a system of individual eyepieces. These celluloid eyepieces, which were treated with an anti-dimming solution, were easily removed and replaced if damaged. A spare set was carried in a pocket within the mask's waterproof storage satchel.