By Mr. D. Beaton. 



403 



Mr. Harris, wishing to ascertain how far Mr. Herbert's re- 

 commendation of summer bottom heat was applicable to the cul- 

 ture of such plants, ordered a glass-case, in which our Auri- 

 culas are wintered, to be placed over a bed of hot dung. On the 

 top of the dung we put a layer of rough stones and gravel, and 

 three or four inches deep of light compost was placed over the 

 whole. In this we planted upwards of a hundred Cacti of dif- 

 ferent species. The case was well suited for the object Mr. 

 Harris had in view; as it had moveable sashes at the sides and 

 at both ends, with a span roof of glass, and by removing the side 

 and end lights, the plants were as much exposed to the currents 

 of the air, as if they had been planted out in the open border. 

 The plants for this experiment were mostly newly imported one.-, 

 and for the first month after planting them the case was kept 

 quite close, after that, the side and end lights were opened, and a 

 constant draught of air was admitted day and night; the plants 

 were syringed every evening in hot weather. After four months' 

 treatment in this way the result was completely successful. Some 

 of the Mexican Mammillariae had made roots ten inches long in 

 that time ; and contrary to their natural habits in some cases, their 

 roots crept along close to the surface of the soil. The roots of 

 most Cacti penetrate far into the soil and insinuate themselves into 

 the crevices of stones and rocks, in quest of moisture, but in this 

 instance they kept near the surface where the moisture was sup- 

 plied; a curious instance of the capability of plants to accom- 

 modate themselves to particular circumstances. 



We have also grown Cacti in constant bottom heat for the last 

 three years with uniform success, especially our seedlings, of 

 which we possess many thousands. This has been effected by a 

 simple contrivance which can be imitated in any house heated 

 either with flues or pipes. It is this,— a shelf of thin Welch slate 

 runs along the whole front of the Cactus house, one side of which 

 rests between two courses of bricks in the front wall, the other on 



