292 Merits and Demerits of Iron Hot-houses. 



this insect in a hot-house where French beans and other cu- 

 linary vegetables are necessarily grown. 



I endeavoured to pursue a regular system in the appli- 

 cation of the moisture, and the point of condensation was re- 

 gulated by the hygrometer invented by Mr. Daniel, taking as 

 a guide the degree of atmospheric vapour that generally pre- 

 vails in tropical climates, and which (as I understand) seldom 

 varies more than five or ten degrees from the temperature of 

 the air. At the time I commenced this mode of treatment 

 the pine plants were in a very unhealthy and stinted state, and 

 some vines in the house were absolutely covered with red 

 spider ; in a very short time the spider was entirely eradi- 

 cated, and the pines wonderfully improved. 



I consider so minute a regulation of the quantity of water 

 applied for saturating the house to be by no means requisite; 

 the same practical effects may be produced in regulating the 

 quantity of moisture, by the indications of the thermometer, 

 which certainly every one who superintends the management 

 of a hot-house must necessarily consult. The hygrometer is, in 

 the first instance, very expensive, which expense is increased 

 by the consumption of ether on every observation being made. 



I have now stated what I regard as the principal objections 

 to a hot-house for the cultivation of the pine apple constructed 

 of the curvilinear iron bar, and have also pointed out by what 

 means I effectually obviated those objections. I will now en- 

 deavour to enumerate the various benefits that attend it, which, 

 under a proper management, will, I think, be found to pre- 

 ponderate in its favour. 



What can be more desirable for a gentleman to exhibit as a 

 prominent feature in his dessert, than a handsome grown, large- 

 sized, and delicious-flavoured pine apple? Yet how much 

 more must its value be enhanced in his estimation, if he can 

 produce this at a season of the year when no such thing can 

 be had in the country ! I have no hesitation in saying, that 

 by cultivating pines under a curvilinear bar, the season will 

 be accelerated at least two months in the size and flavour of 

 the fruit, if a proper system of management is in other respects 

 pursued. 



In confirmation of this assertion, I will mention an instance 

 which came under my own immediate observation. In No- 

 vember, 1825, some New Providence and Enville plants 

 showed fruit, which swelled extremely well ; the Providence 

 from small plants, weighed about 5^1bs., they ripened early in 

 the spring, and were pronounced by an eminent fruiterer in 

 London as the handsomest grown he had ever seen, and mv 



