An all-around solution

It is widely appreciated that smooth stones, such as those that are found in the beds of fast-moving rivers, roll more efficiently than irregularly shaped stones. Until recently, this had been a little more than a curiosity of nature – a bit of trivia that proved useful at the games played during celebration of the summer solstice. Last autumn, it was suggested by the cliff dwellers of the Northern Valleys that this effect could be used to ease the transport of heavy objects. It was demonstrated that smooth rocks of similar size could be placed underneath the object to be moved. The object could then be pushed, the rocks underneath it allowing for the object to slide.

While this approach has many advantages over traditional movement (such as dragging objects across bare earth), there remain a number of impediments to its widespread use. First, it requires the accumulation of multiple smooth stones of similar size, which may be a problem for people who live in regions that are round-stone-poor (such as a field with slow moving rivers). Second, each time the object being moved translates forward, it is required to move stones from the back of the object (which will be newly uncovered) to the front of the object. Thus, continuous movement of the object requires the involvement of multiple people. Finally, there is a limit to the size and roundness of stones that can be practically used in this method. Too large of stones are too heavy to move and replace, too small of stones must be replaced too frequently. In addition, efficient transport requires that the stones be equally round in all directions. Again, this constraint limits the usefulness of this approach to people that have a ready and ample source of stones.

Now, a group of hunters and gatherers from the southern plateaus have devised a method for using single stones to transport goods. They report that holes may be drilled through round stones and a wooden stick passed through this hole. A load may then be placed on the ends of this stick and the resulting contraption pushed. The ingeniousness of this approach is that the stick (which they are calling an “axel”) prevents the stone from moving away from the object that is being transported. In this manner, a single stone may be used to transport any object – overcoming the first two limitations of the previous method. Moreover, there are fewer restrictions placed on the stone being used (both in size and roundness) allowing for more efficient use of round-stone resources.

It remains to be seen how general these results are. For instance, can any stone be used? What about round wooden objects? Is there a fundamental limitation on the size of object that be transported for a given size of stone? Despite these questions, it seems likely that this approach will offer at least a partial solution to the problem of long-distance transportation of objects. For this, the people of the southern plateaus are to be congratulated.