A new and deadly form of warfare is the use of Gas. Until April, 1915, we knew nothing about it and then we had to face it to our great cost. We had no masks and no apparatus of any kind to help us combat it. Having been taken by surprise in an engagement that almost cost us Calais, we set to work to devise means to counteract it. The method adopted is the helmet, made of cloth, and very much like a fireman's smoke helmet. It has large goggles similar to the ones that motorists wear. The cloth is kept saturated with a solution of ammonia which acts as a neutraliser of the chlorine gas. A tube passes through the cloth into the mouth, and through this tube the air from the lungs is breathed out. It is, of course, fatal to inhale air through it, and all the air that is breathed in has to be inhaled through the cloth of the helmet.

The importance of training the soldier to be able to meet gas cannot be overemphasised. He should be drilled frequently with the helmet on to accustom him to the feeling of it, and alarms should be sounded from time to time to teach him to don the helmet as rapidly as possible. In some of the military schools in France the men were actually taken without helmets into chambers where there was just enough gas to make them realise it was there, and were then sent into other chambers with a "deadly" mixture of gas with their helmets on. This training makes them realise the importance of helmets.

Many forms of helmets have been used from time to time, and in this matter as in many others we have learnt from our enemies. For the most recent British mask contains the "nosebox" or "beak" which conforms to the German model. As in most other things, simplicity is to be desired where it can be combined with effectiveness, and it is the simplicity of the cloth helmet with the tube that even to-day commends it to many critics above the "box" forms—those that require an independent supply of oxygen. Where men such as gunners are liable to be exposed to fumes for some considerable length of time, either from cylinder gas or from shells or even from tear shells, or must continue at their posts at any costs, an independent fresh air supply is necessary.

Detailed instruction also should be given as to what men are to do during and after the gas attacks; for there are some forms of gas that do not appear to affect the individual at all, and then all of a sudden, when he begins to use his limbs, he drops dead from heart failure. Instruction on this subject must come from the medical and chemical experts who have made a close study of the effects of gas.

Allied to gas is Liquid Fire. This fire is projected in long streams from the nozzles of pipes that come from a high pressure cylinder, sometimes placed in the bottom of the trench, and sometimes carried on the backs of special men. These globules of burning oil that are sent forth reach a distance of thirty or forty feet from the nozzle of the pipe. The effect of liquid fire is more terrible than words can tell, and it requires great bravery on the part of troops to have them advance in the face of these streams.

Clouds of Smoke as well as gas are used. One of the ruses that was adopted at the battle of Loos was to project smoke forward for a few minutes until the enemy should become quite used to it, and then send out streams and waves of gas to take him unawares. These are frightful methods of warfare which the Allies have had to turn to in order not to allow the enemy, from his violation of his pledged word, and contrary to the rules of warfare, to gain an unfair advantage. But there are many of us who believe that no other enemy than the Germans would have descended to these depths of infamy.