MEDIÆVAL JEWISH SCIENCE.
Editor Popular Science Monthly:
SIR: President White, in "New Battles of Science," shows up the reactionary influence of the Christian writers in the middle ages on the knowledge of Nature, beginning with Cosmas Indicopleustes and ending with Albertus Magnus—their denial of the earth's spherical shape, their bringing rain from beyond the firmament, etc., all on the strength of Scripture. Now, 1 am proud to say that my brethren, the Jewish scholars of the middle ages, did nothing to push science backward, but took it up cheerfully where the Greeks had left it. The two leading philosophic works of middle-age Judaism, both written in Southern Spain, and in the Arabic tongue, are the "Moreh Nebochim" ("Teacher of the Perplexed") of Maimonides, strongly rationalising, and therefore ill received by many, and the "Cozari" (feigned conversations with a "Chazar," khan, converted to Judaism), of the great Jewish hymn-writer, Jehuda Hallevi, published in a. d. 1140, thoroughly orthodox. He rejects the metaphysics of Aristotle and of Epicurus, but recognizes what Greece has achieved in physics. Speaking of the Sabbath (Part II, § 20), he assumes for the three Eastern Continents an extent of twelve hours, or 180° in longitude, and a like extent for the ocean, which Columbus had not yet parted in two; he puts Jerusalem midway between Tsin (China) and westernmost Africa, and tells us that when the Sabbath begins there on Friday evening at six it is midnight in China, and still Friday noon in the extreme West. Not exact, according to our lights, but up to all the light of his own time. Elsewhere lie boasts of the astronomic learning of Rabbi Samuel, an early Talmudic writer, and shows that he and his friends studied the stars only for the purposes of the calendar, new moons, and equinoxes, not with any view to horoscopes. He states with pride that, in the rules for killing and examining beasts for food, the Talmud shows more knowledge of the anatomy of the lungs than can be found in Galen. He also claims that long experience had proved the Jewish measurement of the synodic month and tropical year to be more correct than the numbers given by Ptolemy. He finds no occasion to speak of the origins of rains and thunder-storms; but the absurd notion that rain comes from beyond the firmament could never occur to any of the Old Testament writers, who lived on the narrow strip between the Great Sea and the Syrian Desert, and got their rain with the west wind and their dry heat with the dreaded east wind (kadim), nor to any one who read their books in the Hebrew text. The "Cozari" proves that in the darkest ages our race kept its mind unclouded.
The opinion that thunder-storms are the work of the devil or of evil spirits could not grow up among a people who were taught from their childhood to greet lightnings or falling-stars with the benediction, "Blessed be thou, Lord, who doth the work of creation!" and to welcome thunder with the kindred formula, "Blessed be thou, Lord, of whose strength and of whose might the world is full!"
| Respectfully, |
| Lewis N. Dembitz. |
| Louisville, Kentucky, July 11, 1887. |
HATS AND BALDNESS.
Editor Popular Science Monthly:
Sir: A few months ago you published in the pages of the "Monthly" an article on hats as a cause of baldness, which has been extensively quoted and has attracted much attention. I have delayed writing to you on the subject until I had leisure to look up an article written by my father, the late Dr. Austin Flint, nearly thirty-five years ago. I send an extract from this article which appeared as an editorial in the "Buffalo Medical Journal," March, 1853, No. 10, page 651, and was entitled "Hats and Baldness":"... The most characteristic trait of the hat is the tightness with which it encircles the head. Herein consists, in our opinion, its agency in the loss of hair. The stove-pipe hat must needs encircle the head tightly, in order to be secure in its position in spite of wind and other disturbing forces. To appreciate the degree of compression, one has only to note the indentation on the forehead after a tightly-fitting hat has been worn for some time. Everybody knows how commonly this is to be observed. The head is, in fact, pretty firmly ligated while the hat is worn. Now, what must be the effect of this on the circulation? Plainly, the effect is to interrupt the circulation in the scalp above the circle on which the compression is made. It is precisely like tying a cord around the head, sufficiently to diminish, if not stop, for the time, the flow of blood through the temporal and other ar-
