228 On curvilinear Iron Roofs to Hot-Houses. 



My house is fifty feet long, and ten feet wide, and it is 

 heated by a single fire of moderate size ; and I have found 

 that single fire fully sufficient to keep Pine Apple plants in a 

 healthy growing state, in all seasons of the year, without the 

 aid of bark or hot-bed of any kind, and without the protec- 

 tion of any kind of covering.* I have always used it as a 

 fruiting-house, and my plants, after being placed in it, have 

 grown admirably, and have shown fruit well ; but the fruit 

 has never till the present year, except in one instance, when 

 the plants stood close to the door, swelled properly. Its 

 taste and flavour have nevertheless been good, and it con- 

 stantly ripened in a singularly short time. 



The fruit which appeared in September and October, in 

 the last autumn, became ripe in J anuary, and whenever one 

 fruit became ripe, its aroma appeared to accelerate the matu- 

 rity of all in its vicinity. 



The Queen Pine Apples were generally very similar to 

 those I have usually seen at the shops in London in the 

 months of April and May ; and with imperfections arising, 

 I believe, from the same source, the want of efficient 

 ventilation. 



In houses of ordinary construction, with roofs of sliding 

 lights, air enters and escapes at all times with much rapidity ; 

 and the consequent change of air is very nearly, if not wholly, 

 sufficient to enable the Pine Apple to acquire maturity and 



* A much higher temperature than my machinery enables me to give, and 

 varying from 75° to 90° in winter, and from 80° to 105° in summer, would, how- 

 ever, be highly beneficial : and I feel quite confident that in a dry stove of such 

 temperature, Pine Apples might, under appropriate management, be abundantly 

 ripened, and in considerable perfection, in any part of the year. 



