In the case of some of the unfinished and broken axes found in the Swiss lakes, and even in some of the objects made of stag’s horn,[160] there is a projecting core[161] at the bottom of the unfinished hole. This is also often seen in[162] Scandinavian and German specimens. Dr. Keller has shown that this core indicates the employment of some kind of tube as a boring tool; as indeed had been pointed out so long ago as 1832 by Gutsmuths,[163] who, in his paper “Wie durchbohrte der alte Germane seine Streitaxt?” suggested that a copper or bronze tube was used in conjunction with powdered quartz, or sand and water. In the Klemm collection, formerly at Dresden, is a bronze tube, five inches long and three quarters of an inch in diameter, found near Camenz, in Saxony, which its late owner regarded[164] as one of the boring tools used in the manufacture of stone axes. This is now in the British Museum, but does not appear to me to have been employed for such a purpose. The Danish antiquaries[165] have arrived at the same conclusion as to tubes being used for boring. Von Estorff[166] goes so far as to say that the shaft-holes are in some cases so regular and straight, and their inner surface so smooth, that they can only have been bored by means of a metallic cylinder and emery. Lindenschmit[167] considers the boring to have been effected either by means of a hard stone, or a plug of hard wood with sand and water, or else, in some cases, by means of a metallic tube, as described by Gutsmuths. He engraves some specimens, in which the commencement of the hole, instead of being a mere depression, is a sunk ring. Similar specimens are mentioned by Lisch.[168] Dr. Keller’s translator, Mr. Lee, cites a friend as suggesting the |50| employment of a hollow stick, such as a piece of elder, for the boring tool. My experience confirms this; but I found that the coarse sand was liable to clog and accumulate in the hollow part of the stick, and thus grind away the top of the core. If I had used finer sand this probably would not have been the case. Mr. Rose[169] has suggested the use of a hollow bone; but, as already observed, I found bone less effective than wood, in consequence of its not being so good a medium for carrying the sand. Mr. Sehested,[170] however, who carried out a series of interesting experiments in grinding, sawing, and boring stone implements, found dry sand better than wet, and a bone of lamb better than either elder or cow’s-horn for boring.