Roger Bacon, whose estimates of his contemporaries have sometimes been accepted at too high a value, wrote of Neckam some fifty years after Alexander’s death: “This Alexander wrote true and useful books on many subjects, but he cannot with justice be named as an authority.”[578] Bacon himself, however, seems on at least one occasion to have used Neckam as an authority without naming him.[579] On the other hand, another Englishman of note in science, Alfred of Sarchel or Sareshel, dedicated his book on The Movement of the Heart (_De motu cordis_) to Neckam. [Sidenote: His attitude toward natural science.] Whatever Neckam’s own scientific attainments may have been, there can be no doubt that he had a high regard for scientia and that he was not wanting in sympathetic appreciation of the scientific spirit. This fact shines out in the pages of the _De naturis rerum_ amid its moral lessons and spiritual illustrations, its erroneous etymologies and popular anecdotes. “Science is acquired,” he says in one passage, “at great expense, by frequent vigils, by great expenditure of time, by sedulous diligence of labor, by vehement application of mind.”[580] But its acquisition abundantly justifies itself even in practical life and destructive war. “What craftiness of the foe is there that does not yield to the precise knowledge of those who have tracked down the elusive subtleties of things hidden in the very bosom of nature?”[581] He often cites these experts in natural science, whom he always seems to regard with respect as authorities.[582] Not that he believes that they have solved all problems. Some things forsooth are so hidden that it seems as if Nature is saying, “This is my secret, this is my secret!”[583] On the other hand, there are many natural phenomena too familiar through daily use and experience to need mention in books, since even those who do not read are acquainted with them. Neckam consequently will follow a middle course in selecting the contents of his volume. [Sidenote: Science and the Bible.]