A new obstacle had, however, arisen. With the morning a dense fog had set in, rendering it impossible for the troops to see even a few yards in advance of them. Still they pushed on and, unopposed, reached a point opposite Omichund's garden, but divided from it by the Mahratta Ditch. Presently they heard the thunder of a great body of approaching cavalry. They waited quietly until the unseen horse had approached within a few yards of them, and then poured a mighty volley into the fog. The noise ceased abruptly, and was followed by that of the enemy's cavalry in retreat. The fog was now so dense that it was impossible even to judge of the directions in which the troops were moving. Clive knew, however, that the Mahratta Ditch was on his right and, moving a portion of his troops till they touched this, he again advanced, his object being to gain a causeway which, raised several feet above the country, led from Calcutta, across the Mahratta Ditch, into the country beyond. Towards this Clive now advanced, his troops firing, as they marched, into the fog ahead of them, and the guns firing from the flanks, obliquely, to the right and left. Without experiencing any opposition Clive reached the causeway, and the Sepoys, turning to their right, advanced along this towards the ditch. As they crossed this, however, they came in the line of fire of their own guns, the officer commanding them being ignorant of what was taking place in front, and unable to see a foot before him. Charlie, closely accompanied always by Tim, was at the head of his troops when the iron hail of the English guns struck the head of the column, mowing down numbers of men. A panic ensued, and the Sepoys, terror stricken at this discharge, from a direction in which they considered themselves secure, leaped from the causeway into the dry ditch and sheltered themselves there. Charlie and his companion were saved by the fact that they were a few paces ahead of the column. "Run back, Tim," Charlie said. "Find Colonel Clive, and tell him that we are being mowed down by our own artillery. If you can't find him, hurry back to the guns, and tell the officer what he is doing." Charlie then leaped down into the ditch, and endeavoured to rally the Sepoys. A few minutes later Clive himself arrived, and the Sepoys were induced to leave the ditch, and to form again by the side of the causeway, along which the British troops were now marching. Suddenly, however, from the fog burst out the discharge of two heavy guns, which the enemy had mounted on a bastion flanking the ditch. The shouts of the officers, and the firing of the men, indicated precisely the position of the column. The grapeshot tore through it, and twenty-two of the English troops fell dead and wounded. Immediately afterwards another discharge followed, and the column, broken and confused, bewildered by the dense fog, and dismayed by the fire of these unseen guns, fell back.