Filling a canteen
The most common technique was to place your empty canteen upright on the ground. Then you carefully lifted the water can and began pouring your 4-inch stream of water onto the 1-inch neck of the canteen.
Another method was to place the water can on the ground and hold the mouth of your canteen up to the lip of the water can. Then you tilted the water can slowly forward until water began to run out, catching as much as possible with the canteen. Either way, a lot of water got wasted, especially when the water can was full or if your canteen fell over. By the time the water can was half empty, it was easier to focus your “pour” and get more water into the canteen.