are liable to be occupied by people during a thunder-storm—an iron balcony, for instance. In such cases it is better not to have the iron connected with the conductor, for there is some risk of persons standing on the balcony furnishing a path for the lightning to the rod.
North American Archæology.—The directors of the Smithsonian Institution contemplate the publication of an exhaustive work on the antiquities of North America, and earnestly invite the coöperation of archæologists and of all who may be possessed of information concerning the aboriginal history of North America. The ancient monuments to be described in the work are mounds and earthworks, shell-heaps, cave and cliff dwellings, masonry, sculptured slabs or carved images, inscriptions, and rock paintings, graves and cemeteries, aboriginal quarries, and salt-works, caches or deposits of objects in large quantities, workshops or places of ancient aboriginal industry, ancient roads or trails, reservoirs and aqueducts. In addition to original records and descriptions of the objects here enumerated, the Smithsonian Institution desires to obtain copies of all books, memoirs, pamphlets, extracts from periodicals, and newspaper clippings, having any relation whatever to American archæology. Information is further solicited concerning all collections of American antiquities, however small, whether in private hands or in public museums. Any one can obtain, on application to the Smithsonian Institution, its "Circular in Reference to American Archæology," in which are stated in detail the different subjects concerning which specific information is wanted.
A New Fact in Natural History.—In the books of Leviticus and Deuteronomy it is forbidden to eat any creature living in the waters that "hath not fins and scales." Of such animals it is written: "They shall be an abomination unto you; ye shall not eat of their flesh, but ye shall have their carcasses in abomination." Christians, at least modern Christians, are not wont to hold oysters as "unclean" and "an abomination, "notwithstanding the very high authority on which they are so declared to be in the Holy Scriptures. But the Jew still obeys the divine command, as of old; hence the devout Hebrew knows nothing, from personal observation, of the delicate flavor of the oyster, and no doubt that savory bivalve has oftentimes been a stumbling block and a scandal for the weaker ones of the children of Israel. But a truly wonderful discovery has been made by a learned rabbi in England, which takes the oyster out of the class of things forbidden, and makes it as harmless to the conscience as, doubtless, it will be grateful to the palate of the Jew. This rabbi has read Mr. Darwin's works, and read them to some purpose, for he finds that, "in consequence of the theories" of that famous naturalist, "oysters are plants, and may therefore be eaten by Jews." We hasten to add that as yet the rabbi's views are merely matters of private opinion, and hence no safe guide for consciences; but a grand council will before long be summoned to render authoritative judgment in the matter. Its decision will be awaited with no little interest. It is to be hoped that the vegetable side will prevail. One strong argument in its favor is the notorious fact that oysters are planted, the result of course being the oyster-plant.
Peculiarities of Vision.—Mr. Galton, in his paper on "Composite Portraits" (see page 465 of this number), observes that "the two separate impressions received by the brain through the stereoscope do not seem to be relatively constant in their vividness, but sometimes the image seen by the left eye prevails over that seen by the right, and vice versa." This remark has elicited from a correspondent of Nature a communication in which he describes a very curious defect in his own eyesight. This correspondent's right eye is fairly long-sighted, but the left eye is short-sighted. Print which is read distinctly by the one at the distance of eighteen inches, cannot be easily read by the other at a distance of over eight and a quarter inches. The result of this is, that the right—the long-sighted eye—closes involuntarily when he reads. Again, when he looks intently at a distant view, the left or short-sighted eye shuts occasionally. When both eyes are open he has two sep-