112 Ornamental Grass Gardens. 



The ventilation by the heating apparatus I leave to Mr. 

 Sylvester to describe. Its full heating power we have not 

 yet had occasion to try, not having had any intense frosts. As 

 far as it has been tried, I am satisfied that we have gained a 

 desideratum in heating large houses. We were at a loss 

 how to heat this immense house, steam not being thought 

 sufficient unless the pipes were kept above ground ; and Mr. 

 Sylvester's hot-air stove, with which he proposed to heat it, 

 would have produced too arid an atmosphere for luxurious 

 vegetation. I suggested to Mr. Cockerell the possibility of 

 combining the two together ; he instantly saw the advantage 

 to be obtained by so doing, and we have as yet every reason 

 to be satisfied with the result. The medium fire heat kept 

 up may be stated at 45 degrees. 



I am, dear Sir, yours, &c. 



P. M'Arthur. 



The Grange, Nov. 15th, 1825. 



Note. This opinion of Mr. Sylvester's mode of heating is 

 amply confirmed by a subsequent letter from Mr. M'Arthur, 

 dated the 1st of March last, received since the above was 

 sent to press. 



Art. III. On Cultivating a Collection of Grasses in Pleasure- 

 grounds or Flower-gardens, and on the utility of studying the 

 Graminece. By Mr. George Sinclair, F.L.S., H.S., &c. 

 Nurseryman, Author of Hortus Gramineus Woburnensis. 



{Continued from page 29.) 

 Different species of grasses affect different soils and situ- 

 ations, but generally in combination ; in few instances solitary. 

 The Aira prsecox, on elevated, dry, and poor sands, where the 

 whole plant scarcely attains half an inch in height, the Fes- 

 tuca ovina, Festuca vivipara, Poa alpina, Nardus stricta, Melica 

 cserulea, &c. on heaths aud alpine situations, are in general 

 solitary, growing in separate tufts or patches ; the Arundo 

 arenaria, Elymus arenarius, and Festuca rubra, on the blowing 

 sands of the sea coast ; the Glycerea fluitans, Aira aquatica, and 

 Poa aquatica, in water, are almost the only exceptions to the 

 almost universal law in the natural economy of the grasses, 

 viz. that of growing in intimate combination with each other. 

 If we may be allowed the expressions, the greater part of this 

 family of plants are gregarious, while but few are solitary. In 

 a recent publication on the subject of grasses (Hort. Gram. 

 Wob. 2d. edit.), the above facts are illustrated by a number 

 of details deduced from actual cultivation of the different 

 species of grasses during a series of years. The facts there 



