heat is a substance, viz., caloric.[1] His opinion that colour is a modification of the rays of light[2] is felicitous. He refers constantly in the New Atlantis to the value of the microscope. Speaking of Sylva Sylvarum, I, Nichol says: "Nowhere do we find a closer approximation to the true conception of the law of gravity than when it is stated that it worketh more weakly as it recedes from the earth, 'because the appetite of union with dense bodies is made more dull by distance.'"[3] Just as Aristotle made many valuable biological observations, so did Bacon make many valuable botanical observations. Nicol again, referring to Sylva Sylvarum, V, VI, VII, says that Bacon's 'Georgics of the Earth' "show the almost unparalled range of his interests, and relate to a subject he had really studied and they have called forth the enthusiastic praise of modern botanists."[4] In Nov. Org., II, 45, 48 (9), Bacon recognises the probable or possible influence of the moon on tides. But over against these favourable instances of Bacon's achievements in discovery (the number could be considerably increased) are to be set instances unfavourable. Thus, he still clings to the old theory that some things are naturally hot and others cold. He erroneously believed that the moon's rays are devoid of heat.[5] He is wrong when he says that metal becomes warm more slowly than air, oil, and water;[6] when he says that cold contracts all bodies.[7] His theory of windmills in the Historia Ventorum reveals "looseness of mind."[8] Iron is not ultimate in hardness,[9] as the diamond is harder than iron. "The want of attention to the discoveries of Galileo made him commit himself to an opposition (the more pronounced as he grew older) against the Copernican theory of astronomy."[10] Aristotle held in opposition to Empedocles that the transmission
