Adelard may believe in the marvelous virtue of emeralds, to which indeed he alludes rather inadvertently, but we do not find in the _Natural Questions_ any of the common tales concerning remarkable animal sagacity or malice. This may be mere accident or it may be due to his warning in introducing the discussion of animals to give and take reason only. However, the question is discussed whether the brutes possess souls,[79] and he states that the common people are sure that they do not, and that only philosophers assert that animals have souls. This does not mean that their souls are rational, however: either animals possess “neither intelligence nor discretion but only opinion which is founded not in the soul but in the body”; or perhaps they have “some judgment why they seek and avoid certain things,” and such discretion of sense as enables a dog to distinguish scents. If they possess such animal souls, do these perish with the body? [Sidenote: The earth’s shape and center of gravity.] Adelard is correctly informed as to the shape of the earth and its center of gravity. Asked how the terrestrial globe is upheld in the midst of space, he retorts that in a round space it is evident that the center and the bottom are the same.[80] This thought is reinforced by the next question, If there were a hole clear through the earth and a stone were dropped in, how far would it fall? Adelard correctly answers, Only to the center of the earth. The same question is asked of Adelard by a Greek in the _De eodem et diverso_, so that, in case we regard the _De eodem_ as written before the _Natural Questions_, it would appear that he had not derived his conclusion in this matter from either the Greeks or the Arabs. However, we have heard Plutarch scoff at the statement that bars weighing a thousand talents would stop falling at the earth’s center, if a hole were opened up through the earth.[81] [Sidenote: Indestructibility of matter.] In a recent review of Sir William Ramsay’s _The Life and Letters of Joseph Black, M.D._, it is stated, “The nature of the experiment he (Black) made is not now known, but his tremendous comment on it was, ‘Nothing escapes!’ Have we here really the first glimmering of the great principle of the indestructibility of matter which, with the associated principle regarding energy, forms the foundation of modern chemistry and physics?”[82] To this the answer is, “No.” Adelard of Bath stated the indestructibility of matter eight centuries earlier, and apparently not as the result of any experiment. But his utterance was fuller and more explicit than that of Black. “And certainly in my judgment nothing in this world of sense ever perishes utterly, or is less today than when it was created. If any part is dissolved from one union, it does not perish but is joined to some other group.”[83] [Sidenote: Also stated by Hugh of St. Victor.]