90 BOAED OF AGRICULTURE. 



and a humble beginning, for the first mention of glass struct- 

 ures. In 1619, at Heidelberg, on the Rhine, Solomon de Caus 

 built a movable house, with side sashes, for the purpose of 

 sheltering orange-trees during the winter. It was put up at 

 Michaelmas and removed at Easter. But for the reason that 

 the roof was dark, or for some other cause, the trees did not 

 thrive, and the experiment was not considered successful. 



In 1684 a permanent orangery was erected in the Apothe- 

 caries' Garden at Chelsea, now a part of London. It retained 

 the opaque roof, the sides only being of glass. 



An orangery with a glass roof was built at Wallaton Hall, 

 Nottingham, in 1696. In the year 1717, Switzer, and soon 

 after Miller and Bradley, published plans for houses with glass 

 roofs. Several houses are mentioned as built during this cen- 

 tury, conspicuous among which are the old Stove, at Kew, one 

 hundred and fourteen feet long, built in 1760, which I am 

 told is standing; also an orangery one hundred and forty-five 

 feet long, thirty feet wide and twenty-five feet high, built in 

 the year following. But so little progress was made that 

 nearly a half century later, in 1809, a patent was obtained by 

 Dr. Anderson for houses with glass roofs and a proper slope. 

 This led to the publication of several papers by Knight, in the 

 Transactions of the Royal Horticultural Society, which stimu- 

 lated to a rapid advance, and it was considered that the ulti- 

 matum in form, for the admission of the sun's rays, was 

 reached by Sir G. Mackenzie, in 1815, in the suggestion of the 

 hemispherical figure. 



By way of comparison, I give a brief description of the 

 largest plant-houses of England, France and Russia, — one for 

 each country. 



The Imperial Botanic Garden of St. Petersburg was built 

 by the Czar Alexander, in a. d. 1824, and consists of three 

 ranges of houses, running east and west, aud facing south, 

 each seven hundred feet long, the north and south range being 

 twenty feet wide, and the middle range thirty feet wide and 

 forty feet high, with lights sloping from the top to the ground. 

 These ranges are three hundred and fifteen feet apart, and 

 are connected at each end and also in the centre by three 

 low, double-glazed and span-roofed houses, which are, con- 

 sequently, seven hundred feet long, and. running north and 



