On the River Front, there were three Allied gunboats which cooperated effectively during the first days, but during the latter part of October, when the fight began, these withdrew to Archangel in fear of becoming caught by the ice which formed at the mouth of the Dvina, and then moved slowly upstream against the strong current. It took a week for this ice barrier to travel one hundred miles against the course of the river, so that the enemy had unhindered opportunity to bring up his artillery mounted on watercraft, which he did, and blasted our positions for two weeks after the Allied boats had gone back to winter quarters. Nothing was more discouraging than this hopeless inferiority in long range guns. Assaulting troops, no matter how spirited and courageous, cannot hold their advance in the teeth of a bombardment that scatters emplacements like chaff before the wind and shocks men into a state of insensibility. The stunning effect of massive, high explosives is more important than the casualties caused by direct hits. Nerves are palsied, then fly from control under unremitting blasting salvos. Fortifications are blown to atoms, and debris thrown up like vomit in a deafening belch, a bolt of hottest hell; while the earth quivers like a frightened living thing. And if modern warfare has demonstrated one thing more than any other, it is the prime necessity of artillery support, especially during the attack. After three years' experience, the French and British Staffs laid down the rule that for an offensive to be made with any hope of success, there should be a field gun covering every ten yards of the objective and a heavy gun every thirty yards. The British provided fifty-six heavy guns and howitzers per division, and of these twenty-nine were six inch and over. The French had fifty-eight guns in each division, forty-six of which were six inch and over. These divisions were made up of two brigades of two regiments each, a total of fourteen thousand four hundred men. The Americans in France had two regiments of 75 mm. guns and one regiment of 155 mm. guns for every combat division on the first lines. At Archangel there was not a six inch gun in the Allied Command until the late days of spring when the Americans were evacuated. There was only the Russian naval howitzer on the armored train. And the only other heavy guns were two Four Point Five howitzers of the 41st Royal Field Artillery.