The Birmingham age-herald., 1917-07-08

gas attack Is given. You will see the gas cylinders, artfully concealed. Here and there you may see a mound of earth, solidly buttressed and on 1t a machine gun, so placed that 1t fires in either of two directions and con- trols two approach trenches. Or you will stumble into 8 little recess and as you grope about hn the darkness you will become conscious of a spot of light. Look through the hole which let's that light in and you will see that 1t covers a goodly section of No Mans Land. It is a sniper's post. At the School of Military Engineering you can do what you never can do in France. You can climb over the par apet and look at this post from the outside. You can look at 1t, I say I don't say that you can see it. The trick which hides 1t Is too good to tell the Germans. Besides, the censor wouldn't let it pass. That is one of the thousand things our boys must learn when they get here.
 Travel back now through the com munication trench. You will see that every 50 feet or so the trench seems to run into blind alley with bay window effect at the end. That is q convenience when two bodies of men have to pass each other in the IT0nCne5- lie T6GSSSSS diC aASO uScl LII when Germans are coming down the trenches, because you can hide In the deep recess and hold your rifle trained on the trench. It Is a very desirable place.
 As you pass to the base line the work of the royal engineers becomes more and more important Here you have dugouts, one. two and three levels underground, with twisting tunnels, InI traps and tricks. Here you have bomb ing pits and machine gun emplace- ments, snipers posts and hidden trench mortars Here you may have light railway, adapted to hand power only, and used for bringing up food and to have a "strong point"
 The Strong point" is the concentrated development of the trench system, the sapper's pride. By definition a strong point is a section of trench which can be held against an enemys attack with out reference to the fate of any other section of the same trench system. It Is really young fortress. But the def milton doesn't begin to tell what a strong point may be. I cannot describe it in too much detail because 1t Is just as well that the Germans should find out these little things for themselves But generally speaking a strong point will have:
 l. A center. 1fllS VIII usually pc a circular position supplied with snipers posts and machine gun emplacements. Both of these will control all the ap- breaches to the center. There may be a long straight trench on one side and a series of zigzags on the other. The guns are so placed that virtually every foot of ground can be covered by fire.
 ?. Traps.
 3. Dugouts. For extra men, waiting to take their turn at the work of holding the strong point and for men arriving by the
 4. Communications. Strong points will be dotted over the trench system in a rough circle. At the center will be the keep the whole will be known as a Labyrinth" The strong points communi- cate with each other and with the cen tral point and the whole thing Is so ar ranged that although each strong point can count on all the others for support, any one can be held when the others have fallen.
 5. Bombing pits, munition dumps cam ouflage 6or deceiving aviators), supplies of flares, signals, etc.
 6. A telephone system, possibly field wireless, supply of explosives, for nlin- ing and sapping, first aid post and probably some sort of kitchen. These adjuncts will usually be on the second and third levels down. The first level will be for the dugouts.
 In the German retreat which preceded the battle of Arras the Royal Engineers had work more to their liking. They went on with the advance, and as they came to town after devastated town the Royal Engineers examined the ground. spotted for concealed wires, tested innocent looking dressers and pianos for explosives. shot up jugs of wine left suspicinously behind