PHYSALIS maturity is thin, five-angled, much netted, and completely envelops the fruit in a balloon- shaped covering much larger than itself. The species most generally cultivated in this coun- Winter Cherry (Physalis Peru viana) Flower and Leaves. try is P. Perumana (P. edulis and P. esculen- ta of some authors), which is known as straw- berry tomato, ground and winter cherry, and yellow alkekengi ; in England it is called Cape gooseberry, and by the French cerise d'hiver and cerise de Juif. Its specific name indicates its native country. Its pale yellow flowers are spotted with purple ; the fruit is about half an inch in diameter, yellowish or amber-colored, and semi-transparent at maturity, the calyx becoming a dull yellowish or light drab color. The berries enclosed in the calyx fall as soon as full grown, and do not usually reach com- plete ripeness until they have "been kept for some days ; they have a decided fruity flavor, something like that of the strawberry, though the after taste is not so pleasant; if spread thinly and kept from freezing, they retain their qualities through the winter; preserved with sugar with the addition of lemon juice, they make an acceptable sweetmeat. The cultiva- tion is the same as that for the tomato ; the plants come up abundantly from self-sown seed, Fruiting Calyx, and Calyx opened. and it is disposed to be a weed. The alke- kenp (from the Arabic, P. alkelcengi), from the south of Europe, has smoother leaves than the preceding, greenish white unspotted flow- ers > a brilliant scarlet berry, and the husk or PHYSICAL GEOGRAPHY 481 enclosing calyx of the same color, rendering the plant quite ornamental; the fruit has similar qualities to the preceding, but it is very much less cultivated in gardens. The calyx of both species is used in making skeleton bouquets, the cellular tissue being separated by macera- ting and leaving only the network of fibres. The native P. Philadelphia is nearly smooth, with an erect stem and yellowish flow'ers which are dark colored in the centre, and has a glo- bose calyx completely filled by a dark purple berry an inch in diameter ; it is abundant in some southern and western localities, and is sometimes cultivated as the purple alkekengi, purple strawberry tomato, &c., for its fruit, which is used for preserving. PHYSICAL GEOGRAPHY, that department of the science of geography which treats of the physical condition of the earth, describing its character and relations as a member of the solar system, explaining its great natural divi- sions of land and water, the atmosphere, and the great movements, as of oceanic and aerial currents, which variously affect and modify these features. The forms of continents and oceans and of their subdivisions, the heights and ranges of mountains, the phenomena of deserts and plains, and all the varying outlines f r*om the highest mountain summits to the low- est depths of the sea, are among the first ob- jects of its consideration. The geological struc- ture of the earth and all meteorological phe- nomena belong to the broad field of its investi- gations ; which also comprises the natural pro- ducts of the earth, vegetable and animal. But comprehensive as is its range, it does not en- ter into individual descriptions of phenomena, localities, and species, but is concerned chiefly with general laws and principles, as they are manifested upon a grand scale, and in the or- ganic kingdom with the existence of races and their distribution in certain zones or stations of habitation. The relations and adaptations of organic and inorganic nature to each other are specially treated in this science alone. Its ultimate aim, as stated by Humboldt in his " Cosmos," the work which first gave to physi- cal geography a special place among the sci- ences, "is to recognize unity in the vast di- versity of phenomena, and by the exercise of thought and the combination of observations to discern the constancy of phenomena in the midst of apparent changes." The first wri- ters on physical geography were among the earliest geographers and writers on physical science, and have been referred to in the arti- cles EARTH and GEOLOGY. The broad views advanced by Thales, Pythagoras, Aristotle, Strabo, Pliny, and others of the ancient phi- losophers and geographers, entitle them to be regarded as the first cultivators of this sci- ence. In modern times its principles have been treated with great originality and ability by the Jesuit Jose de Acosta, in his Historia natural y moral de las Indias (Madrid, 1590). In 1650 was published the first edition of the
