78 ON THE MBRITS OF IRON AND WOOD FOE ROOFS. 



the particulars of the culture of the Gladiolus Psittacinus. May 

 fine large roots, when planted in the open ground, be depended 

 on flowering? if so, at what time should they be planted? If pot- 

 ted and raised in a hot-bed, do they require much or little water? 

 in short, should they be well watered under all, or any circum- 

 stances ? I presume that the full grown roots shoxdd be taken 

 up in the autumn : as they do not die down early, perhaps the 

 end of October would be the best time. 



As to the young roots I observe that they come up luxuriantly 

 in the spring when left in the ground ; I succeeded tolerably well 

 with these roots last year by raising them first in a hot bed, being 

 potted the beginning of March, then placing them in a green- 

 house till the beginning of June, when they were planted in the 

 borders ; but they did not quite realize my expectations, having 

 seen them growing more luxuriantly at the Horticultural Gardens, 

 therefore I am desirous of knowing the best method of proceed- 

 ing with them Some roots that I left in the ground through the 

 winter, rotted, at least the hearts dwindled away, sending up 

 an immense quantity of young ones in their places. 



It would be desirable to grow them without first raising them 

 in a hot bed : but of those that I have planted in the gound few 

 have flowered. I believe they require a sunny situation. 

 Clapham, 12th January, 1838. 



ARTICLE IV. 



ON TOE RELATIVE MERITS OF IRON AND WOOD ROOFS. 

 STOVES, GREENHOUSES, &c 



(continued from PAGE 7'i) 



Having, I think, fully shown, the advantage possessed by wood 

 over cast iron in those very essential points ; the better growth 

 of plants, and the saving of fuel, glass, and labour ; I shall now 

 add to these observations a few words on the various systems of 

 heating houses ; that is to say, with common flues with steam, 

 and by the circumvolution of hot water. The last named method 

 is now becoming very general, and is admitted by all scientific 

 men to be the best, because it is the safest; the most certain, 

 and no doubt when perfectly fitted upon a good principle, it is 

 also the most economical as regads the expenditure of fuel and 



