There is a passage in this treatise “On the Nullity of Magic” of remarkable character, as exhibiting the achievements, or, if not the actual achievements, the things esteemed possible by the inventors of the thirteenth century.  There is in it a seeming mixture of fancy and of fact, of childish credulity with more than mere haphazard prophecy of mechanical and physical results which have been so lately reached in the progress of science as to be among new things even six centuries after Bacon’s death.  Its positiveness of statement is puzzling, when tested by what is known from other sources of the nature of the discoveries and inventions of that early time; and were there reason to question Bacon’s truth, it would seem as if he had mistaken his dreams for facts.  As it stands, it is one of the most curious existing illustrations of the state of physical science in the Middle Ages.  It runs as follows:—­“I will now, in the first place, speak of some of the wonderful works of Art and Nature, that I may afterwards assign the causes and methods of them, in which there is nothing magical, so that it may be seen how inferior and worthless all magic power is, in comparison with these works.  And first, according to the fashion and rule of Art alone.  Thus, machines can be made for navigation without men to row them; so that ships of the largest size, whether on rivers or the sea, can be carried forward, under the guidance of a single man, at greater speed than if they were full of men [rowers].  In like manner, a car can be made which will move, without the aid of any animal, with incalculable impetus; such as we suppose the scythed chariots to have been which were anciently used in battle.  Also, machines for flying can be made, so that a man may sit in the middle of the machine, turning an engine, by which wings artificially disposed are made to beat the air after the manner of a bird in flight.  Also, an instrument, small in size, for raising and depressing almost infinite weights, than which nothing on occasion is more useful:  for, with an instrument of three fingers in height, and of the same width, and of smaller bulk, a man might deliver himself and his companions from all danger of prison, and could rise or descend.  Also, an instrument might be easily made by which one man could draw to himself a thousand men by force and against their will, and in like manner draw other things.  Instruments can be made for walking in the sea or in rivers, even at the bottom, without bodily risk:  for Alexander the Great made use of this to see the secrets of the sea, as the Ethical Astronomer relates.  These things were made in ancient times, and are made in our times, as is certain; except, perhaps, the machine for flying, which I have not seen, nor have I known any one who had seen it, but I know a wise man who thought to accomplish this device.  And almost an infinite number of such things can be made; as bridges across rivers without piers or any supports, and machines and unheard-of engines.”  Bacon goes on to speak of other wonders of Nature and Art, to prove, that, to produce marvellous effects, it is not necessary to aspire to the knowledge of magic, and ends this division of his subject with words becoming a philosopher:—­“Yet wise men are now ignorant of many things which the common crowd of students [vulgus studentium] will know in future times."[40]