We also meet at Senegal with a tree which I ought, perhaps, to have ranked of right among those of India, and which, like many others, belong rather to the whole zone of the Tropics than to any particular country; I refer to the Tamarind (_Tamarindus Indica_),[166] whose well-known name is supposed to be derived from the Arabic _Tamar_, signifying "dates," and _Indus_, in allusion to its original habitat. There is only one species of the genus, but the East Indian variety has long pods, with six to twelve seeds, while the West Indian has much shorter pods, containing one to four seeds. It is a tree of graceful appearance, with elegant pinnated foliage and numerous racemes of fragrant flowers. The pods are slightly curved, and consist of a brittle brown shell, enclosing a soft, acid, brown pulp, traversed by strong woody fibres; a thin membranous covering wraps up the seeds. The pulp has a savour at once acid and sugary, and acts as a gentle laxative. The timber is useful for building purposes, and furnishes excellent charcoal for the manufacture of gunpowder. The _Sterculiaceæ_ have numerous representatives at the Senegal. These tall and handsome trees remind the traveller in their appearance of our English oaks. The seeds of the _Sterculia acuminata_ and _tomentosa_ are masticated by the negroes until reduced to a fluid paste, in which form they employ it to dye their cotton-stuffs yellow. The dye is very bright, and, it is said, extremely durable. We know that a great part of the Gaboon is occupied by virgin forests, where Fig-trees are predominant, and in marshy soils the Mangle or Mangrove trees (_Rhizophora mangle_), which must not be confounded with the savoury-fruited Mangoes of Eastern India. The Mangroves form, in the family of the _Rhizophoras_, a genus distributed in the moist localities of the Tropics, and we shall hereafter meet with them in South America. Equatorial Africa possesses several species of Palm-trees peculiar to it. Such are the Thorny Date-tree, the _Borassus_ of Ethiopia, the _Raphia vinifera_ of Congo, which, as its name "wine-bearing" indicates, furnishes a wine analogous to that extracted in other regions from other trees of the same family; the _Elæis Guinensis_, or Guinea Palm, whence we obtain the well-known product of palm oil. This oil, or palm-tree butter, forms an important article of food among the Guinea negroes. It is imported into Europe in large quantities, and employed in the manufacture of soap.