CONTENTS. Page. ORIGIN of the Horticultural Societies Early attention of these societies to artificial climates Attention of scientific men and gardeners, previously to the establishment of these societies, Mr. Knight's improvements and writings the most important in respect to hothouses Important principle of the slope of the roof introduced by Mr. Knight BOERHAAVE the first who laid down principles for the slope of glass Laurence, BradLEY, LONDON and WISE, SWITZER, MILLER Mr. KNIGHT applied the principle to forcing houses, and illustrated it more fully Mr. WILKINSON's formula for the application of the principle... SIR GEORGE MACKENZIE'S extension of the principle Examination of the form of house proposed by Sir George Mackenzie Description of vineries and peach-houses on this construction Description of the arrangement suitable for a pinery on this plan Arrangement for opening the sashes in houses of this description Great advantage of metallic sashes over wooden ones Comparative advantages of different descriptions of glass roofs Outer or inner curtain recommended for hothouses Objections to the use of metals in the roofing of hothouses answered The Plates are printed by Mr. Daniel Redman of Somers Town, from sketches made on REMARK S. PART I. On the Principles of CONSTRUCTION, &c. PERHAPS ERHAPS at no period since the days of Evelyn and Miller has horticulture assumed so respectable an attitude among rural and œconomical pursuits as at the present time. The horticultural societies of London and Edinburgh, composed of men of rank and influence, scientific amateurs, and practical gardeners, give a degree of eclat and salutary consequence to the study; and from this circumstance, as well as the known skill and activity of many of their members, the public may expect to reap considerable advantage. The origin of these associations, as well as of the present taste for horticulture, may in a great degree be ascribed to the physiological inquiries of Mr. Knight, the president of the London Society; and to the taste and patronage of Sir Joseph Banks. To Mr. Knight the philosopher is indebted for some interesting experiments on the vegetable œconomy communicated from time to time during the last twenty years to the Royal Society; and the gardener for much scientific discussion and valuable practical instruction relative to the culture of fruits, contained in his "Treatise on the Apple and Pear," and in various papers in the London Horticultural Transactions;-the result of this B gentleman's enthusiastic pursuit of a favourite study for many years. The taste, judgement, and influence, of Sir Joseph Banks, especially in whatever relates to the study of Nature; his unequalled library in that branch of science; and his friendly protection of those who devote themselves to its study; are too well known to require eulogium. It is justly remarked by an accomplished agricultural writer, that by the devotion of a long life and ample fortune to the pursuit and encouragement of a useful and peaceful branch of human knowledge, he has obtained honour, enjoyed self-satisfaction, and laid the foundation of a fame as extended as civilization, and as permanent as the history of letters1. It may readily be supposed that the subject of artificial climates, which by enabling the horticulturist to exhibit spring and summer in the midst of winter, and bring to perfection the delicious fruits and splendid flowers of the torrid zone in a temperate or cold country,which gives man so proud a command over Nature, and renders a skilful practitioner in such requisition among the opulent,—would receive an early attention from these societies. Accordingly we find Mr. Knight, in his introduction to the published Transactions of the London Society, doubting as to the perfection of the construction of hothouses, "two of which," he observes, "are rarely constructed alike, though intended for the same purpose:" and among the papers subsequently given to the world, are some valuable communications on the subject by the same philosopher, and by Sir Joseph Banks, Mr. Wilkinson, Mr. Williams, Sir George Mackenzie, and several others. The increasing taste for exotic botany, and more general demand for the culinary luxuries of hothouses, had, previously to the establishment of the London Horticultural Society, produced considerable emulation among scientific men and gardeners, relative to the improvement of their construction. Besides various local alterations, attended with different degrees of success, patents were taken out by Mr. Hoyle, 'Dr. Anderson in Recreations in Agriculture and Natural History. Dr. Anderson, Mr. Stuart, Mr. Jorden, and subsequently by Mr.Wecks, Mr. Kewley, and others. Some of these inventions have not had sufficient trial, and others have by ulterior changes been long since “réduits au mérite historique.” Of these improvements, and of the various papers published by the horticultural societies, none are more calculated to promote the art of perfecting artificial climates, than the communications of Mr. Knight "on the construction of peach-houses and vineries1;" and the discussion to which these papers have given rise, on the slope which the glass roofs of hothouses ought to have, in order to receive the greatest possible benefit from the sun's rays at the proper season of the year. The important principle of adapting the slope of the glass to the object in view, thus recognised and established by Mr. Knight, has long been known to scientific men on the continent, and more or less generally in Britain since Miller's time. It must be confessed, however, that in this country and for the last half century it has been almost wholly lost sight of, or neglected as of little importance. In this period, that description of glass houses, adapted for forcing or maturing tender fruits, had greatly increased. It became the fashion to have hothouses; and these edifices, from being the study of the philosopher, became articles of trade, and taste and science gave way to number and magnitude. Horticulture improved by the Flemings was in great repute in all the Low Countries during the seventeenth century?. Botanic gardens, which were first established in Italy about the middle of the sixteenth century3, soon found their way there. That of Leyden was founded in 1575, and the celebrated L'Ecluse caused to be constructed in it a conservatory in 1599. A century afterwards (about 1709) six houses of different descriptions for the protection of exotics were erected un 1 London Hort. Trans. vol. i. Lobel, Histoire des Plantes, 1576. 3 Zannoni, Istoria Botanica, Bologna, 1675, |