Another lighthouse was built a few years afterwards, but was burned down, it being of wood instead of stone. At last the work was put into the hands of Smeaton, who saw that he must build on a totally new plan. He took for his model the trunk of a tree, and determined to build his lighthouse of the same form as the tree-trunk, and to fasten it into the rock just as a tree is fastened by its roots. Accordingly, he struck out a new principle in the construction of such edifices, and his model has been followed ever since. The reader will see, by a glance at the illustration, how close is the resemblance in external form. I may mention that the tree in question was sketched from one in a paddock opposite my house. [Illustration: TREE-TRUNK. EDDYSTONE LIGHTHOUSE.] Having settled the form of the lighthouse, and made it like a tree-trunk, the next business was to fix it firmly in the rock, and, in fact, to give it roots of stone. For this purpose, he made the base of the edifice as wide as the rock would allow, so as to correspond with the wide base of a tree-trunk, and traced a circle of about ninety feet in circumference. Instead, however, of merely laying the stones as is usually done, or even letting them into holes cut in the rock, he hit upon a singularly ingenious device, whereby the building was practically a single stone. Instead of cutting the stones square or oblong, as is usually done, he had them made so as to “dovetail” into each other, much after the fashion of a child’s puzzle toy, or the junctions at the edge of a box. Thus, each stone fitted into those around it, while the lowest tier was dovetailed in similar fashion into the rock. [Illustration: SUTURES OF SKULL SECTION OF EDDYSTONE LIGHTHOUSE DOVETAILED BOX] The stone employed was that which is called Moorstone, a very hard variety of granite. Each course of stones was carefully fitted together on shore, and their accuracy tested, and they were then taken to the Eddystone rock, and fixed in their places. Beside using these precautions, Smeaton fixed the stones in their place with the strongest cement, and furthermore fastened the stones together and united the several courses by strong oak treenails and iron clamps. As none of the stones weighed less than a ton, and some of them were double that weight, the strength of such an edifice may be imagined. The accompanying illustration shows the arrangement of these dovetailed stones in one of the courses. It will be seen that the central stone must be laid first, and then the others arranged round it. The whole edifice is rather more than eighty-five feet in height, so that the elements have every chance of demolishing it, as they did that of Winstanley. More than a hundred years have now passed since it was built, and, although the fury of the tempest has been such that the waves have washed completely over its summit, it stands as firmly as it did when it was finished in 1760. * * * * *