Of course Fritz’s liberality with his gas shell caused us a lot of casualties, but not nearly so many as we might have had if he had known how to use them. The fact was he had not at that time got hold of the proper technic--developed later on by the French--of concentrating his gas shell on special targets. By now, of course, he has; but at that time he still clung to the idea of being able to poison big areas with his shell gas by putting down a series of barrages over the country to be attacked. Either he had not enough shell or he chose his areas too big, for he did not produce effective concentrations anywhere but locally. If he had, our losses might have been tremendous. As it was it became rather a hit-or-miss proposition, and I have seen hundreds and hundreds of these shell drop into absolutely unpopulated areas of the devastated Somme battlefield. In one case a battery of field guns came in for its share of one such promiscuous bombardment while I was there. The number of shell coming over was so great that it was like a magnified machine-gun shoot, but only a very few got on to the battery and the casualties were only two--both caused by a direct hit on one of the guns by a gas shell. If the boche had been able to concentrate his shell on and round the battery instead of giving it just the same amount as the unoccupied surrounding country the effect might have been very different. One possible reason for the promiscuous and sometimes very casual shooting may have been the fact that the boche at that time had practically no air observation. Our flying fellows had temporarily chased his planes out of the skies and had shot down all his observation balloons. This made it impossible for him to pick his targets, and he either had to bombard the countryside or shoot “by the map,” neither method being particularly conducive to good results with gas shell. On the other hand, one or two places that he knew were pretty certain to be occupied by our troops were given their full dose. One such place was Caterpillar Wood--a big narrow spinney running off from the Fricourt Valley and so named because of its shape and the fact that on the ordnance maps, on which the woods are colored green, it looks just like a green caterpillar crawling over to the shelter of Mametz Wood. This place was continually shelled with large numbers of the Green Cross Shell, and as it stood in the side of a valley the gas persisted longer there than elsewhere and built up a tidy concentration which caused a lot of trouble.