124 Mode of warming and ventilating Hot-houses 



and enthusiastic for the propagation of his plan, will carry it into 

 execution in any part of the United Kingdom at less cost, and, 

 as being the inventor, more successfully, than is likely to be done 

 by any other person whatever. 



We shall now state what we consider to be the principal ad- 

 vantages of Mr. Penn's improvement. 



1. The heat of air in motion, whether dry or charged with 

 moisture, is never felt by the human body to be so hot or oppres- 

 sive as when it is stagnant. This every one will recollect to be 

 the case, when he thinks of what were his feelings during a hot 

 summer's day, when there was no breeze, and when there was a 

 breeze. We could not have believed that the difference would 

 have been so great in a hot-house, had we not experienced it. 

 We remained in Mr. Penn's orchidaceous house about half an 

 hour, with the temperature about 80°, and in his pine-pit about 

 the same time, without feeling the slightest inconvenience ; so 

 much so, that we could have passed the da}', with pleasure, in 

 such a temperature. We felt as if we were in the open air, in 

 a fine summer's day, and experienced none of the disagreeable 

 effects of stagnant and sometimes fetid air, which are so often 

 experienced in hot-houses, particularly in those in which the 

 Orchidacese are grown. The same thing, Mr. Penn observed, 

 had been noticed by a number of persons, including ladies, who 

 stated that they could never remain more than a few minutes in 

 their stoves at home, while they could have remained all day, 

 and even slept, in Mr. Penn's. An analogous effect was expe- 

 rienced at the North Pole, by Captain Parry and his compa- 

 nions : when the air was perfectly still, the extreme cold of that 

 region was bearable ; but the moment the slightest breeze arose, 

 it became intolerable. We had no means of trying the moisture 

 of the air by a hygrometer, but that the moisture must have been 

 considerable, was evident from the water in the drains, and the 

 dew on the plants. 



This alteration in the sensible effect produced by hot moist 

 air on the human frame, we consider to be the great advantage 

 of Mr. Penn's improvement, because it will henceforth render 

 plant stoves of every kind, including even orchidaceous houses, 

 fit for being entered into, and even lingered in, by the most deli- 

 cate, as well as the most robust, constitutions. 



2. By the circulation of the air, blossoms of every kind will 

 be made to set better, fruit will be produced of higher flavour, 

 and leaves and blossoms of more intense colour. We had a 

 proof of these results. In one house there were strawberry plants 

 in pots just going out of flower, and Mr. Wilmot, who was pre- 

 sent, declared that the fruit was as well set as if the plants had 

 been in the open air, though the sashes of the house had not 

 been opened, nor any fresh air admitted but what entered through 



