208 On Pemi's Mode of Warming and Veritilatiiig. 



open air, 12 ft. long, and 3 ft. 6 in. wide ; drive seven notched 

 pegs, 2 ft. apart, down the centre of the bed, to stand 1 ft. above 

 ground ; and seven down each side, at the same distance apart, 

 but only 4 in. out of the ground ; then, to make the sides and 

 gable ends, take a piece of turf, 4 ft. by 4 ft., shaped out with 

 the edging-iron, and taken up with the turfing or floating spade, 

 1^ in. thick, of the proper shape, so that it may be set on edge 

 and kept so by a peg on each side, and having the green side 

 out. When the lights are put on, with every alternate one 

 higher than, and embracing the iron edge of, the two under it, 

 you will have a very elegant little flower-house, which a labourer 

 might erect in an hour with sixpenceworth of building mate- 

 rials, and the finished structure would have thus every other 

 light hinged, and ready to admit air, or allow of watering and 

 gathering flowers, like a complete forcing-house." This box 

 may be used in the open ground for forcing sea-kale, rhubarb, 

 and for a variety of other purposes. We regard it as promising 

 to be one of the most useful and economical inventions that have 

 been introduced in horticulture in our time. — Cond. 



Art. III. On Mr. Penns Mode of Warming and Ventilating. 

 By James Main, A.L.S., &c. 



Mr. Penn's new method of maintaining a constant current of 

 warm air through forcing-houses appears to be a very great 

 improvement, as affecting the health of the plants. Air in 

 motion has always been considered more salubrious to plants as 

 well as animals, than that which is stagnant, whether moist or 

 dry. The ascending growth of trees has ever been attributed to 

 the action of the wind upon their stems and branches, which, 

 by bending them forwards and backwards, gives to the rising 

 sap a kind of pulsation, a diastole and systole, of ihe membranes 

 producing enlargement. Farmers maintain that turnips grow 

 fastest in windy weather ; and I knew of an experiment made on 

 one plant to prove the truth of this idea. A turnip-hoer marked 

 a single plant near the gate of the field in which he was employed, 

 and every time he passed in or out, turned the plant first to the 

 right and next to the left, during about a fortnight he was at 

 work in the field. The plant was evidently assisted by this 

 manipulation, and exceeded in bulk the other plants that grew 

 around it ; and which circumstance put an end to the experiment, 

 for a liquorish cow-keeping boy made free with the favourite, 

 before it was the size of a walnut. 



My own opinion on this matter is, that the frequent fracture 

 of the fibres on each side, caused the emission of an additional 



