120 Mode of warming and ventilating Hot-houses 



The double stopcock will afford the means of occasional sepa- 

 ration of the bag, and of examination of the contained air under 

 the influence of different circumstances. 



In the section Jig. 18. a shows the check or rebate in the top, 

 which lifts up, and is faced with wash-leather ; h, the drip for 

 the condensed moisture from the glass ; c, the glass frame screwed 

 down en the soil box, with a slip of wash-leather between them ; 

 d, the soil in the box; e, the lining of lead, with an inner lining 

 of thin wood; j*^ the bottom of the soil box; and g^ the frame on 

 which the whole rests. 



As before observed, I planted the case with some hundreds of 

 bulbs of various sorts on December 28. ; and, at the same time 

 placed some of the same bulbs in earth in garden pots, and 

 others in water glasses. Those in the case are distinctly gaining 

 on those in the pots and glasses, and will flower before them. 

 The case stands in a window, facing a little to the eastward of 

 south, and gets what sunshine the season affords. There is no 

 fire in the room, and the temperature near the window rarely 

 exceeds 60° ; the pots and glasses are in a window looking 

 N.N.W., but have the advantage of from 2° to S° of higher 

 temperature during the day ; in the night time the whole house 

 is nearly uniform, at from 57° to 60° [being heated by one of 

 Silvester's cockles, as will be described in our Supplement to the 

 EncyclopcBdia of Cottage Architecture']. 



I have heard lately of some curious cases of the roots of plants 

 running to a distance in search of bones, and then insinuatino; 

 themselves into every crevice within them. I recollect also ob- 

 serving at Malmaison that many plants which had been inserted 

 in skulls of animals, were flourishing in a remarkable manner. 

 This leads me to ask you whether bones and bone-dust have 

 been much tried in horticulture, and whether you would counsel 

 me to try some in the case, when in May next it is prepared for 

 its permanent inhabitants. [We shall be glad of a hint on this 

 subject, or on any other relative to this article, from any cor- 

 respondent.] 



Edinburgh) Randolph Crescent, Jan. 20. 1840. 



Art. IX. Some Account of a Mode of tvarniing and ventilating 

 Hot-houses invented and applied by John Penn, Esq., Engineer^ 

 Sfc, at his Residence at Lewisham, in Kent. By the Conductor. 



The first attempt that was made to heat hot-houses by hot 

 air was, we believe, made by Dr. Anderson, in a green-house 

 attached to his dwelling-house at Isleworth, about 1802, as de- 

 scribed in his Descriptio7i of a Patent Hot-house, published in 



