The advantages of these wooden bellows are very great. When made of clean fir-wood without knots, they will last thirty or forty years, and even longer, though continually kept in action forty-six or forty-eight weeks every year: nay, Polhem assures us, that, when properly made, they will last a century. The effect produced by them is stronger, as well as more uniform, and can be moderated according to circumstances. They are worked also with greater facility. The slips of wood on their sides are apt to become damaged; but they can soon and easily be repaired. Every three or four months, however, the outer sides only of the inner box, and the bolt which keeps the boxes together, must be smeared with oil. If we reckon up the price of such bellows, and the yearly expense, they will, according to Grignon’s account, be only a fifth part of those of the old leather bellows. That the invention of these wooden bellows belongs to the Germans, is certain. Grignon[145] expressly affirms so; and in Becher’s[146] time they were to be found in Germany, but not in England. Genssane, who ascribes the invention to the Swiss, is certainly mistaken; and perhaps he was led into this error, because these bellows were first made known in France by a Swiss. I cannot, however, ascertain the name of the real inventor. In the middle of the sixteenth century lived at Nuremberg an artist called Hans Lobsinger, who, in the year 1550, gave to the magistrates of that city a catalogue of his machines. From this catalogue Doppelmayer concludes that he understood the art of making small and large bellows without leather, and entirely of wood, which could be used in smelting-houses and for organs, and likewise copper bellows that always emitted a like degree of wind. As Lobsinger made organs, he, perhaps, fell upon this invention; but in what it actually consisted, or whether it might not have died with him, I have not been able to learn. Agricola, who died in the year 1555, makes no mention of wooden bellows. Samuel Reyher, formerly professor at Kiel, in a dissertation on air[147], printed there in 1669, tells us, that about forty years before that period, two brothers, Martin and Nicholas Schelhorn, millers at the village of Schmalebuche in Coburg, first invented wooden bellows. Both the brothers, he says, kept the invention secret, though he thinks they did not conceal it so closely as to prevent its being guessed at; and he relates also how he himself formed an idea of it[148].