and of Rural Improveme7it generally^ during 1841. 579 



market-gardener, and other gardeners and amateurs, passed on 

 it at the time that it first attracted attention. The two chief 

 objections to it are, that it is not so economical in point of con- 

 sumption of fuel as the best ordinary modes, and that it is less 

 certain in regard to atmospheric moisture. While we concede 

 these points, we are far from agreeing in all that has been said 

 against the system ; and we should certainly employ it under 

 particular circumstances, such as in a conservatory or green- 

 house attached to a house, or in a low wide pit, to circulate the 

 air from the back to the front. We wish, however, to consider 

 the merits of Mr. Penn's system rather as under trial than as 

 finally settled ; and to be determined at some future time, when 

 the present excitement respecting it is somewhat allayed, and 

 when those who write on it shall have the truth for their object, 

 and not that of merely its condemnation or defence. The most 

 rational and unimpassioned discussion which we have seen on 

 the subject is contained in some very excellent articles in the 

 Gardener's Chronicle^ by Alfred Ainger, Esq., in favour of 

 radiant heat. The essence of all of these articles will be found 

 in our General Notices (p. 634-.), but the papers themselves well 

 merit the attentive perusal of the scientific gardener. 



Mr. Corbett's mode of heating, by the circulation of hot water 

 in open gutters, appears to be generally approved of, more es- 

 pecially for houses or pits of limited extent, and where all the 

 pipes can be laid on levels. The conducting of the heating 

 pipes through troughs of water (p. 635.) seems also to be much 

 liked. A mode of ventilation, by the introduction of fresh air heated 

 by passing it through hot-water pipes, described by Mr. Green 

 (p. 637.), promises well, and we shall be glad to hear more respect- 

 ing it. A similar mode of introducing fresh air to the conservatory 

 in the Chelsea Botanic Garden was tried by Mr. Watts in 

 Evelyn's time, the pipes being passed through the furnace ; 

 but in this case, and also in that of heating by fresh air in Mr. 

 Sylvester's mode, it has been found that the current of heated 

 air when once established is continued after the fire becomes 

 low, till at last cold air instead of heated air is admitted into the 

 house. In the case of admitting heated air through hot-water 

 pipes, as the temperature will probably be lower, the influx of 

 air from without will not be so rapid, and, consequently, it will 

 be more likely to stop at the proper point. Mr. Green informs 

 us, however, that the current of air does continue after the fire 

 gets low or goes out; and that he, therefore, considers it most 

 advisable to have the ventilation tubes open only when the water 

 is sufficiently heated to warm the air which passes through it; or 

 when the external air is mild enough not to require much heat- 

 ing. Mr. Green considers that this mode of ventilation will be 

 of the greatest service in forcing-houses and in stoves. 



p p 3 



