It likewise appears that the water-wheels to which Heliogabalus directed some of his friends and parasites to be tied, cannot be considered to be mills for the purpose of grinding corn; for these, as well as the haustra of Lucretius were probably like those machines for raising water, which are spoken of by Vitruvius as hydraulic.
It is, however, on the authority of Pompinius Sabinus, before-cited, that both wind and water mills were known to have been in Italy, and even the latter in Rome, in the days of Augustus. However, about twenty-three years after the death of Augustus, when Caligula seized every horse from the mills, to convey effects he had in contemplation to take from Rome, the public were much distressed for bread; whence we must infer that water-mills must have been very rare. Even three hundred years after Augustus, cattle mills were so common in that city, that their number amounted to three hundred; mention of them, and of the hand-mills, often occurs for a long time after. It is not their use we inquire after, it is enough for us to know that they existed.
We now come to another period, when we are informed that public mills were first introduced, which occurs in the year 398, mention being made of them in that year, which also clearly shows that they were then newly-established; which establishment was found necessary to be protected by laws made in their favour. The orders for that purpose were renewed more than once, and made more secure by Zeno, towards the end of the fifth century. It may be properly remarked, that in the whole code of Justinian, the least mention of wooden pales or posts is not made, which occurs in all the new laws,—and which, it appears, when there were several mills on the same stream, occasioned so many disputes then, as well as in after times. The mills at Rome were erected on those canals which conveyed water to the city; and because these were employed in several arts, and for many purposes, it was ordered that, by dividing the water, the mills should always be kept going; but as they were driven by so small a quantity of water, they probably executed very little work; and for this reason, but probably on account of the great number of slaves, and the cheap rate at which they were maintained, these noble machines were not so much used, nor were so soon brought to perfection, as under other circumstances they might have been. It appears, however, that after the abolition of slavery, they were much improved, and more employed, and to this a particular incident seems, in some degree, to have contributed.
When Vitiges, King of the Goths, besieged Belisarius in Rome, in the year 536, and caused the fourteen large expensive aqueducts to be stopped, the city was reduced to great distress; not from want of water, in general, because it was secured against that inconvenience by the Tiber; but by the loss of that water which the baths required, and, above all, of that necessary to drive the mills, which were all situated on these canals. Horses and cattle, which might have been employed upon grinding, were not to be found; but Belisarius fell upon the ingenious contrivance of placing boats upon the Tiber, on which he erected mills that were driven by the current. This experiment was attended with complete success; and as many mills of this kind as were necessary were constructed. To destroy these, the besiegers threw into the stream logs of wood, dead bodies, &c., which floated down the river into the city; but the besieged, by making use of booms to stop them, were enabled to drag them out before they could do any mischief. This seems to have been the origin of floating-mills, no record of them appearing previously. By these means the use of water-mills became very much extended; for floating-mills can be constructed almost upon any stream, without forming an artificial fall; they may be stationed at the most convenient places, and they rise and fall of themselves with the water.—They are, however, attended with these inconveniences: they require to be strongly secured; they often block up the stream too much, and move slowly; and they often stop when the water is too high, or when it is frozen.
After this improvement, the use of water-mills was never laid aside or forgotten, but was soon made known all over Europe; and passages innumerable might be quoted, in every century, to prove their continued use. The Roman, Salic, and other laws, constantly provided for the security of these mills, and defined a punishment for such as destroyed the sluices, or stole the mill-irons. It is said, however, that there were water-mills in France and Germany a hundred years before these laws had existence.
At Venice, and other places, there were erected mills which regulated themselves by the motion of the waters, and which were regulated by the flowing and ebbing of the tide, and which every six hours changed the motion of the wheels. Of this species of mills, a new invention, or, perhaps, rather an improved one, was made in London, called a tide-mill, an engraving of which may be seen in “The Advancement of Arts, Manufactures, and Commerce,” London, 1772.
Zanetti is said to have shown, by some old charters, that such mills existed about the year 1044; but with still more certainty in 1078, 1079, and 1107.
It appears, however, that hand and cattle mills were in most places retained, after the use of proper watermills, particularly in convents. They were used, because the otherwise lazy monks found the exercise they afforded beneficial to their health. Likewise the legends of popish mythology are full of the miracles which have been wrought at these mills.
A modern author of credit impeaches the veracity of Pomponius Sabinus after he had previously quoted his authority, and likewise after he had said that he bore a good character, in a popular work, by charging him with improbability, nay, positive falsehood, and alleging that the Romans had no wind-mills. It should be noticed, without venturing to decide upon the point, that he has adduced no authority for such allegation, and that he only concludes so, by inference, as upon the authority of Vitruvius; that mechanist, he says, in enumerating all moving forces, does not mention wind-mills. But, for the sake of candour, was not the one as liable to err as the other? He also says, that neither Seneca nor St. Chrysostom mention wind-mills; and is unmercifully severe upon an old Bohemian annalist who speaks of wind-mills so early as 718. But he is all along bringing his forces to prove, that wind-mills had first existence in his own district, Germany; that they were then invented; and, perhaps, because he is of that country. It is somewhat remarkable that scarcely any invention of any consequence has occurred since that of printing, but the honour has been claimed by the natives of Germany.
Mabillon mentions a diploma of the year 1105, in which a convent in France is allowed to erect water and wind-mills, molendina ad ventum.