362 



Of Forcing Hoases, Cooservalories and other structiiics of 

 tliekind, we have seen that they were known to the Romans, 

 and in this country in the seventeeth, if not at the close of the 

 sixteenth Century. At first they were merely heated sheds, 

 without windows for the admission of light. In the French 

 Trar^/ener Evelyn mentions their being constructed with windows. 

 These structures were rudely heated by burning charcoal in 

 holes made in the floor of the house. This continued as late 

 as the middle of the seventeenth Century. In the first years of 

 the 18th Century regular structures with glass roofs were 

 introduced. Between the middle and close of that century 

 Speechley erected the magnificent Pineries at Welbeck ; Aiton 

 and Sir W. Chambers raised the plant stoves at Kew ; and 

 Abercrombie, Nicol, Kyle, &c. proportionably contributed to 

 the improvement of such structures. They continued however 

 chance- directed edifices until the commencement of the present 

 century. In 1809 Dr. Anderson and the President of the Lon- 

 don Horticultural Society in 180G, roused the attention of Gar- 

 deners to the subject; the first by his philosophical reasoning; 

 the latter by the same united to the voice of experience. Mr- 

 Knight directed his remarks chiefly to demonstrate the proper 

 angle for glass roofs of Hot-houses ; they gave rise to the pa- 

 tent structures of Stewart, Jordan and others ; and these 

 were still farther improved on the firm basis of mathematical 

 demonstration in 1815 by Sir G. Mackenzie, who shewed what 

 is now confirmed by practice, that an hemispherical glass roof 

 admits the most rays of light. This was further advocated by 

 Mr. Loudon in 1817. 



Another improvement, also a birth of the present Century, is 

 forming the frames of the houses of Cast Iron instead of Wood. 

 The plan of heating Hot-houses by flues is owing to the Duke 

 of Rutland about 1717. Steam was first employed for the 

 same purpose by Mr. Wakefield of Liverpool in 1788 ; and 

 more effectually by Mr. Butler, Gardener to the Earl of Derby 



