The men were all acquainted with the process, which was a simple one. A deep hole was dug in the ground. The bottom of this was lined with clay, hollowed out into a sort of bowl. The hole was then filled with the roots of fir closely packed together. When it was full a fire was lit above it. As soon as this had made its way down earth was piled over it and beaten down hard, a small orifice being left in the centre. In this way the wood was slowly converted into charcoal, and the resin and tar, as they oosed out under the heat, trickled down into the bowl of clay at the bottom. As little or no smoke escaped after the fire was first lighted, the work could be carried on without fear of attracting the attention of any bodies of the enemy who might be searching the country. Two months passed. By the end of that time the intrenchment on the river bank had been made so strong that it could resist any attack save by a very large body of men. That on the island had also been completed, and strong banks thrown up at the only three points where a landing could be effected from boats. The swamps had been thoroughly explored in the neighbourhood, and another island discovered, and on this three hundred men had been established, while four hundred remained on the great island, and as many in the camp on the river. There were over a thousand women and children distributed among the three stations. Three hundred men had laboured incessantly at the boats, and these were now finished. While all this work had been going on considerable numbers of fish and wildfowl had been obtained by barter from the Fenmen, with whom they had before had dealings, and from other communities living among the swamps to the north. Many of the Iceni, who came from the marshy districts of the eastern rivers, were also accustomed to fishing and fowling, and, as soon as the work on the defences was finished and the tortuous channels through the swamps became known to them, they began to lay nets, woven by the women, across the streams, and to make decoys and snares of all sorts for the wildfowl. The framework for many coracles had been woven of withies by the women, and the skins of all the cattle killed were utilized as coverings, so that by the end of the two months they had quite a fleet of little craft of this kind. As fast as the larger boats were finished they were used for carrying cattle to the islands, and a large quantity of swine were also taken over.