Where are the armies who are to cope with such forces? A few stalwart and grimy men come forward, each man with a curious but unmistakable air of one who wages a war of giants. The furnace door is opened, and out rushes a blinding light which strikes on the eyeballs like a shock of electricity. The men seize the handles of an enormous pair of Pincers, suspended in the middle by a chain, and though no unpractised eye can distinguish the glowing iron from the enveloping fire, they run the Pincers into the furnace, seize the iron, swing it to the anvil, and turn it this way and that way as easily as if it were a feather, while the blows of the gigantic hammer descend upon it, enveloping them in a torrent of sparks which spurt as if they were mere splashes of water, and seem to do them no more harm. Taking the minor exposition of the Pincers principle and their use, we may mention the ordinary Pincers which are mostly used for drawing nails. Then there are the smaller Pincers called Pliers, all of which are constructed on the same principle, and the chief of which are the Round-nosed Pliers, the Long-nosed Pliers, and the Gas Pliers. Sometimes a mixture of the Hammer and the Pincers is ingeniously contrived, as in the tool which is represented on the right hand of the illustration. [Illustration: MUSSEL-SHELL. EARWIG. LOBSTER-CLAW.] [Illustration: SUGAR-TONGS.] [Illustration: PINCERS.] Then we have the still smaller and feebler Pincers of civilised life, such as the Sugar-tongs and the ordinary Coal-tongs of our firesides. Anatomists could have had no practical existence without the Pincers, of which their beautifully constructed and much-elaborated forceps are but variations. Take, again, the dentist, with his series of shining instruments, which he so carefully keeps out of sight until he has got his patient safely in that awful chair, and which glide, as by a conjurer’s trick, empty into an open mouth, and return in a few seconds with a tooth between their polished jaws. * * * * * ALL these instruments have their parallels in Nature, and in many instances the natural pincers might supply useful hints to modern tool-makers. In the left-hand upper corner of the illustration is shown the common fresh-water Mussel, which is so plentiful in almost all our rivers and many of our ponds. Its scientific name is _Unio margaritiferus_. The latter title, which signifies “pearl-bearing,” is given to it because it furnishes the British pearls which were at one time so highly valued. Like other bivalve molluscs, this Unio has the two halves of the shell fitting quite tightly upon each other, and, when they are drawn together by the contraction of the internal muscles, they can give a very severe pinch. In many uncivilised parts of the world the natives take advantage of this property, and use them as tweezers, chiefly for the purpose of pulling out hairs which they are pleased to think are not needed.