982. The science of every art must necessarily depend on the end or object for which that art is practised; on the nature of the materials employed to procure or attain those ends; and on the nature of the agents made use of by human skill to operate on those materials. The object of the art of gardening is twofold: that of cultivating vegetables for use or ornament in domestic or general economy; and that of forming arrangements of external scenery, beautiful as such, and suitable for personal recreation. The first of these objects is by far the more ancient and the more important. Men must have used vegetables as food in the earliest ages of society, and the idea of collecting them, and cultivating them in one place, field, or garden, must have been coeval with the first dawn of civilisation. The first gardens or fields probably contained only the plants necessary for food; and the second, those useful in medicine. As civilisation advanced, the idea must have arisen of growing plants solely for ornament; and the necessary consequence would be a wish to render gardens ornamental. The science of gardening appears, therefore, naturally to consist of four parts: first, the study of the vegetable kingdom, in order that the young gardener may know the nature of the plants he has to cultivate; secondly, the study of the agents of vegetable culture; thirdly, the science of horticulture, to know how to use these agents judiciously; and fourthly, the principles of landscape gardening, or the art of laying out grounds.
