proper or insufficient food ; the periods of the moultings are times of sickness and danger ; great destruction is caused by a disease called muscadine, which is a minute fungus (botrytis Bassiana) occupying the interior of the body and bursting through the skin. The disease called the " reds," manifested by red stains and blotches on the skin, is ascertained to be due to some acid, resulting from disordered digestion ; the larvae seem cramped and stupe- fied, the rings dry up, and they look like mum- mies. The larvae of several large moths of the genus saturnia (Schr.) form cocoons from which silk is obtained ; among these are the arrindi silkworm, S. [Samia~ Cynthia (Schr.), of India, and the 8. mylitta (Schr.), whose moths have an alar expanse of about 8 in., and appear to be the wild silkworms of the East. The 8. mylitta abounds in Bengal, and yields much coarse and dark-colored silk, highly prized by the Hindoos ; it cannot be domesticated ; the natives catch the caterpillars, put them on the asseem trees, and guard them from birds by day and bats by night ; the natural food is the rhamnus jujuba. The S. Cynthia is do- mesticated in the interior of Bengal, on leaves of the castor oil plant (ricinus communis or palma Christi) and of the ailantus glandulosa ; the cocoons are generally about 2 in. long and 3 in. in circumference, whitish or yellowish, of soft and delicate texture. There are eight or ten species of. American silkworms ; the cal- losamia Promethea and 0. angulifera feed on the lilac and wild cherry; others are platysa- inia Euryale, P. Columbia, P. Cecropia, and tropcea luna ; but practically the larva of telea Polyphemus is the only important one. This feeds on the leaves of the oak, maple, elm, willow, and several other trees. For descrip- tions and figures of this species, in all its stages, and the method of rearing the larvaa, see "American Naturalist," vol. i., 1867. . SILLDIAN. I. Benjamin, an American physi- cist, born in North Stratford (now Trumbull), Conn., Aug. 8, 1779, died in New Haven, Nov. 24, 1864. He graduated at Yale college in 1796, was appointed tutor in 1799, and was admitted to the bar in 1802. He accepted the new chair of chemistry at Yale college in 1802, and passed a part of the next two years in Philadelphia, as a student with Dr. Woodhouse. In the win- ter of 1805 he gave his first full course of lec- tures, and shortly after sailed for Europe. He visited the mining districts of England, attended lectures in London and Edinburgh, and resumed the duties of his professorship after an absence of 14 months. He published in 1810 " Journal of Travels in England, Holland, and Scotland in 1805-'6 " (2 vols. 8vo ; enlarged ed., 3 vols. 12mo, 1820). Not long after his return he made a geological survey of a part of Connec- ticut. In December, 1807, a meteorite of great size and splendor passed over New England, and threw off large fragments with loud ex- plosions in the town of Western, Conn. Profs. Silliman and Kingsley visited the town and SILLIMAN procured some fragments ; and Silliman made a chemical analysis and published the earliest and best authenticated account of the fall of a meteorite in America. He afterward assisted Dr. Robert Hare in his experiments with the oxyhydrogen blowpipe, to which he gave the name now commonly used of "compound blow- pipe." In 1813 he published in the "Me- moirs of the Connecticut Academy of Arts and Sciences" an account of his experiments with this instrument, by which he had greatly ex- tended the list of bodies known to be fusible. In 1812 he secured to Yale college the then unrivalled mineralogical and geological collec- tion made by Col. George Gibbs in Europe. In 1822, while engaged in a series of observa- tions on the action of a powerful voltaic de- flagrator on the model of Dr. Hare, he first established the fact of the transfer of particles of carbon from the positive to the negative electrode of the voltaic apparatus, with the corresponding growth of the negative electrode, and the retransfer when the charcoal points are shifted. In 1818 he founded the "Ameri- can Journal of Science and Arts," better known both in Europe and America as "Silliman's Journal," of which for 20 years he was sole, and for eight years more senior editor. He was one of the earliest American lecturers on scientific subjects to miscellaneous audiences, and delivered courses in the principal cities. He published an account of a journey between Hartford and Quebec (1820), an edition of BakewelTs " Geology" (1829), and a text book on "Chemistry" (2 vols., 1830). In 1851 he again visited Europe, and published " A Visit to Europe in 1851 " (2 vols. 12mo, New York, 1853). In 1853 he resigned his professorship, and was made professor emeritus ; but at the request of his colleagues he continued to lec- ture on geology till June, 1855. His life has been written by Prof. George P. Fisher (2 vols., New York, 1866). II. Benjamin, jr., an Amer- ican physicist, son of the preceding, born in New Haven, Conn., Dec. 4, 1816. He gradu- ated at Yale college in 1837, became an instruc- tor there in chemistry, mineralogy, and geolo- gy, and in 1846 was appointed professor of chemistry applied to the arts in the scientific school of the college, now the Sheffield scien- tific school. He became associate editor of the "American Journal of Science" in 1838, and since 1854 has been associated with Prof. J. D. Dana as editor and proprietor. From 1849 to 1854 he was professor of medical chemistry and toxicology in the university of Louisville, Ky. ; and in 1854 he succeeded his father as professor of general and applied chemistry in Yale college, which post he still holds (1876). In connection with C. R. Goodrich he prepared the "Illustrated Record" and the "Progress of Science and Art" published in connection with the international exhibition of 1853 in New York. He was for several years secre- tary of the American association for the ad- vancement of science, and had charge of the
