| Complexene: | 39.0 lbs. | Hexamethylenetetramine |
| 37.5 lbs. | Glycerine | |
| 27.5 lbs. | Nickel sulfate (NiSO₄·7 H₂O) | |
| 11.8 lbs. | Sodium carbonate (Na₂CO₃) | |
| Water | ||
| Greasene: | 107.0 lbs. | Castor oil |
| 81.0 lbs. | Alcohol (95%) | |
| 10.7 lbs. | Glycerine (90%) | |
| 3.1 lbs. | Sodium hydroxide (NaOH) | |
This mask fits the face tightly and as a consequence the inhaled air can be obtained only by drawing it through the pores of the impregnated fabric. There is no outlet valve. The exhaled air makes its escape through the fabric. The eyepieces are made of a special non-dimming celluloid. The mask is protected from rain by a flap of weather proof fabric, which also protects the absorbent chemicals from deterioration.
At the beginning of the war the United States experimented considerably with the French mask. Several modifications of the impregnating solutions were suggested, as well as methods of application. One of these was to separate the components of the complexene solution and impregnate two separate layers of cloth; this would make a three-layer mask. In view of the phosgene which was in use at that time, the following arrangement was suggested:
- 20 layers of hexamethylenetetramine,
- 10 layers of nickel sulfate-sodium carbonate,
- 10 layers of greasene.
This arrangement was more effective than the original French mask and offered the following protection when tested against the following gases (concentration 1 to 1,000, rate 30 liters per minute):
| Phosgene | 65 minutes |
| Hydrocyanic acid | 60 minutes |
| Chlorine | 60 minutes |
Fig. 47.—Interior View
of M-2 Mask.
Fig. 48.—French Artillery Mask,
Tissot Type.