The basis of the whole thing, therefore, was that every officer should see that the men under his command were properly instructed in defensive measures against gas attacks, and that all orders on the subject were thoroughly understood. It was then up to the officers to see that their men could get their helmets on properly in the minimum time, and this involved considerable amount of drill practice. It was pointed out to the officers that since protection had been provided, those battalions which had been carefully instructed had come through practically unharmed, while those battalions in which instructions had been neglected suffered severely. It was also up to the officers to explain to their men as much as they themselves had learned about gas clouds, and to impress on them, for example, that by moving to the rear they would move with the gas, and that if they got flurried they would breathe more deeply and would run much more risk of being gassed. Besides these questions of instruction and drilling a lot of other arrangements had to be made, so that warning of German gas attacks should be spread in the quickest possible time. Arrangements were made to install alarms of various kinds in the trenches. Of course no reliance could be placed on any method of communication which involved the use of the lungs. A man cannot blow a bugle or a whistle while he has a helmet on, and if he waited to give a signal by such a method before protecting himself he would be almost certain to be gassed. What was done was to place bells and gongs made from shell cases up and down the trenches. At first these were rather futile things, the bells generally being much too small--some of them merely cow bells. The shell cases were a bit better and are still used for local alarms; but the arrangements for giving warning were not really very good at that time. The best devices were a number of motor horns, which were obtained locally, but the supply was insufficient and there was no general issue. Later on the alarm arrangements were tremendously improved. In some cases signal lights were used, but so many different kinds of rockets were already employed for signalling to the rear that there was great difficulty in finding a light sufficiently distinctive. There was also the danger that it could be quickly copied by the boche, who would thus amuse himself by giving us all kinds of shocks from false alarms. Quite as important as the provision of signals was the making of observations to see when the wind was in a dangerous quarter. This was done partly at the meteorological stations at headquarters and partly on the front line itself. The latter was regarded at the time as the most important, and orders were given that each unit in the front line should rig up some kind of wind vane and learn to ascertain the strength of the wind, so that they should be immediately prepared for an attack whenever the wind was in a dangerous quarter.