invented by John Penn, Esq., Le*wisham. 121 



1803. The next was by Mr. Stewart, in the large conservatory 

 at Mr. Angerstein's at Blackheath Park, about 1803, for which 

 a patent was taken out by Mr. Stewart. Both these houses we 

 saw in 1803. Neither of these modes of heating by hot air 

 was considered at the time as completely successful : in one case, 

 we believe, because the air was heated by smoke flues, and con- 

 sequently was too dry; and in the other, on account both of the 

 means (the heat of the sun) and the arrangements being inade- 

 quate. Some time afterwards, but at what period we are un- 

 certain, the Messrs. Strutt of Derby applied their cockle to 

 heating hot-houses by a current of air brought from without, 

 with a power of stopping the supply from without, and reheating 

 the air of the house. A vinery at St. Helen's, the seat of Edward 

 Strutt, Esq., M. P., and one at Bridge Hill, Belper, the seat of 

 George Strutt, Esq., continue to be so heated ; and Jedediah 

 Strutt, Esq., has recently heated several hot-houses by this mode, 

 at his residence in the village of Belper, which, as observed in, 

 our volume for 1839, p. 448., appeared to answer perfectly, when 

 we saw it in May last ; an arrangement being made by which 

 the heated air passes over water, and thus becoming charged 

 with moisture, the defect attendant on all the preceding modes 

 appeared to be remedied. The large conservatory at the Grange 

 was heated by hot air from one of Mr. Strutt's cockles com- 

 bined with steam, by the late Mr. Sylvester, in 1825, as noticed 

 by us in our first volume, p. 112. Such is the amount of our pre- 

 sent recollections on the subject of heating hot-houses by hot air. 



Mr. Penn's mode of heating and ventilating by hot air differs 

 from the above modes, in the heating body being pipes of hot 

 water, and in the great simplicity of the arrangements. It ap- 

 pears to us to effect the object much more completely than by 

 any other mode that we have seen ; the great simplicity of the 

 arrangements being such, that, as it appeared to us, no repairs 

 can be required for a number of years to come, not, indeed, till 

 the pipes are worn out. This constitutes its superiority to the 

 mode of heating at Belper and the Grange, which appeared to 

 us rather more intricate. 



The section, j%. 19., will show Mr. Penn's mode of heating 

 almost without explanation. The pipes of hot water which heat 

 the air are shown at a ; the opening by which the air enters the 

 house, at Z» ; c is a grating by which the air is drawn in again, 

 and conveyed along the drain d, to be reheated by the pipes, 

 and again rarefied so as to reenter at h. By these simple and 

 obvious means, the air is in a state of continual circulation, as 

 shown by the arrows in the section. The degree of heat in the 

 house is regulated by shutting, partially or wholly, the openings 

 {b) by covers which are fitted to each. The drains [d) are made at 

 greater or less distances according to the heat required ; and, when 



1840. March. k 



