556 GALACTODENDRON GALAPAGOS by Tomkins and Seniors, was published in London in 1869 ; a translation with notes, by Abdy and Walker, in 1870 ; and a translation and commentary, by Edward Poste, at Oxford in 1871. GALACTODEffDROff. See Cow TEEE. GALACTOMETER (Gr. yaka, gen. ydAa/crof, milk, and pETpov, measure), an instrument for deter- mining the specific gravity of milk. The com- mon hydrometer may be used for this purpose, but a better instrument is that called the cen- tesimal galactometer, invented by M. Dino- court. This is a glass tube made to float up- right in the liquid, and surmounted with a stem upon which are two scales, one intended to be used in skim milk, the other in milk from which the cream has not been removed. The normal range of each quality is designated upon one of the scales, and the divisions above are intended to mark hundredths of water that has been added. Though the specific gravity of genuine milk commonly is found between 1-026 and 1-081, the determination of this is a very uncertain test of its purity. Cream being specifically lighter than milk, its removal leaves the fluid comparatively heavier ; water might be added to this, and the specific gravity be thus brought to that of genuine milk. The instrument therefore should be used only in connection with another called the lactometer, the object of which is to determine the propor- tion of cream present. This being known, and the specific gravity ascertained with the accu- racy due to the graduation of the galactometer, the quality of the milk can be more correctly determined than by other instruments. GALAGO. See LEMUE. GALANGAL, the root of an unknown Chinese plant, probably belonging to the ginger family. Two kinds, the larger (Alpinia galanga) and smaller, are described. It resembles ginger in many respects, and is but little employed in medicine, but occasionally forms an ingredient in some quack formula, or is peddled under some assumed name as a specific for diarrhoea, cholera, &c. It contains a volatile oil, a resin, and various extractive matters. The only ac- tive principles are the oil and resin. It was known to the Greeks and Arabians, and its aromatic and stimulant properties led at one time to its extensive use. Recently discovered agents of similar action but more agreeable taste have superseded it. It may be given in substance or infusion. The dose of the former is about 20 grains ; of the latter, two or three fluid ounces. GALAPAGOS, a group of islands lying in the Pacific ocean, under the equator, about 600 m. from the coast of Ecuador, to which politi- cally they belong. They were discovered by the Spaniards, who named the group from the numerous land tortoises, called galdpagos in Spanish ; but the single islands have received English names. In the latter part of the 17th century they became a great rendezvous of the buccaneers, who resorted to them for re- freshments and to fit out expeditions against the Spaniards. The group consists of six prin- cipal islands, nine smaller ones, and many islets, some being mere rocks. Its northern and south- ern limits (including Culpepper and Wenman islands) are lat. 1 40' N. and 1 27' S., and it lies between Ion. 89 30' and 92 5' W. The largest island, Albemarle, is about 60 m. long and about 15 broad ; it is also the most elevated, reaching a height of 4,700 ft. The next in size is Indefatigable island, after which come Nar- borough, James, Chatham, and Charles. All the islands are volcanic, and with the excep- tion of a few ejected fragments of fused granite, found by Darwin, every part consists of lava, volcanic tuff", basalt, and other eruptive rocks. The general shape of the islands is that of the majority qf oceanic volcanoes, a large dome, surmounted by a wide and shallow crater, and the sides furrowed by numerous lava streams. Small cones of eruption are occasionally seen on the flanks, but are particularly numerous near the foot; Darwin estimates that there are 2,000 of them in the group. The S. W. point of Albemarle island is studded with them. Volcanic activity seems to be nearly extinct at present. On Narborough island two craters were seen in action by H. M. S. Tagus in 1814, and a terrific eruption is described in Morrel's voyage in 1825. Darwin saw in 1835 a small jet of smoke issuing from one of the great craters of Albemarle island. It is certain that on these two islands the lava streams look much fresher than on the others, and the vegetation is much more scanty. As a rule, the volcanoes of the eastern islands ap- pear to have been extinct for a much longer time than those of the western. The climate is remarkably temperate, considering the posi- tion directly under the equator. This is due to the low temperature of the Peruvian current, which coming fromvthe antarctic regions strikes here to the westward after having followed closely up the coast of South America. This current meets here a part of the equatorial current starting from the bay of Panama, so that the curious phenomenon was observed by H. M. S. Beagle of the water being 60 on the southern side of Albemarle island and 80 on the northern. The lower parts of the islands are remarkably arid and destitute of water ; but the summits, which are generally covered by clouds, receive from them sufficient moisture to sustain an abundant vegetation and to be susceptible of cultivation. The rainy season is from November to March, but cannot be com- pared to the continental rainy season. Severe droughts occur occasionally; in 1872, previ- ous to the visit of the United States steamer Hassler, more than 2,000 head of cattle had perished from that cause on Charles island. The Galapagos had no permanent inhabitants till 1832, when a party of exiles were brought over from Ecuador by Don Jos6 Yilamil. The largest settlement is on Charles island, and is called Floriana, at one time containing
