670 Hints for Improvements. 



Tobira, Camellza japonica, and 01ea eiiropae^a and fragrans, stand upon 

 a wall without protection. 



I am trying some others out of doors j if they succeed, I will give 

 you an account of them. I am, Sir, &c. — M. A. Jan. 1. 1829. 



Plans of Gardens and for Systematic Arrangements of Plants. — Sir, 

 Being amongst the earliest subscribers to the Gardener's Magazine, it 

 has been with increased interest that I have perused its columns, as there 

 is manifestly a progressive improvement in each succeeding Number. 

 Writers of more abilities now appear in its pages, and those who were 

 your first correspondents evidently improve in their style of arranging and 

 transmitting their ideas. Those correspondents who intend continuing 

 their communications deserve the highest praise and grateful thanks of 

 every reading gardener. G. W. Johnson is more especially entitled to 

 our thanks, for his valuable papers on Horticultural Chemistry ; as is like- 

 wise " A Landscape-Gardener," for his excellent articles. I hope that prac- 

 tical gardeners will take the hints that the latter gentleman has given them. 

 Juvenis Olitor, I fear, has forgot the proposal he made, of sending the 

 plans of the different structures in the garden plan (Vol. IV. p. 214.), which 

 I and more of your readers would like to see if J. O., will favour us with 

 a continuation of them [in the hands of the engraver]. I beg leave to 

 call your attention to another subject, which opens a wide field in which 

 to exercise the abilities of the young aspiring botanist or gardener; that 

 is, to commence a series of plans for laying out a garden on theJussieuean 

 system of classification, where systematic arrangement will associate with 

 the beauties of Flora to form at once both a flower and botanic garden; 

 to unite nature and art together, both to be visible in the design, but by 

 imperceptible gradations, to be always advancing to or receding from each 

 other ; and for each tribe and genus of plants, whether they be natives of 

 plains, mountains, woods, marshes, rivers, &c., to be assigned a situation 

 congenial to their natural habitats, as far as nature and cultivation can be 

 connected together. I shall add no more at present, but leave the hint to 

 you and your readers. I am. Sir, yours, &c. — J. P. January, 1829. 



Churchyards. — S'n; You have recommended ornamenting churchyards 

 with trees and plants, and rendering them arboretums or flower-gardens. 

 Allow me to suggest the idea of surrounding some of them, in rich parishes, 

 with a colonnade or arcade, which might be built of the material cheapest 

 on the spot, and the interior painted al fresco, as in the Campo Santo at 

 Pisa. The interior of the colonnade of a metropolitan sepulchre might be 

 divided into portions, allotted among the principal historical painters of the 

 day, and the result would be a work unparalleled in the world. But, per- 

 haps, you would like better to have the walls covered with objects of natural 

 history, or casts of all the best pieces of sculpture in the world; to which 

 I have no objection, provided you agree to let me have a part in my own 

 way. The colonnades would require to be glazed like our old-fashioned 

 conservatories. What would not such a colonnade, painted by such an artist 

 as Mr. Haydon, be worth ? Yours, &c. — An Artist. May 10. 1829. 



Transmitting the Heat of Dung by Pipes. — I wish some of your phi- 

 loso[)hical readers would impose upon themselves the task of enquiring 

 whether any real advantage is gained in respect to the resistance of frost, 

 by the insertion, in the body of a hotbed, of the tubes proposed by the 

 President of the Horticultural Society. My doubt originates in the con- 

 sideration, that a given quantity of heat, being generated in a given time 

 by the fermenting dung, is transmitted through the body of the dung to 

 the entire external surface of the bed, and from that surface is communi- 

 cated to the ambient air within the frame. The heat being transmitted 

 from the bed into the ah* in so many points of the surface, the quantity of 

 heat, transmitted at each point of contact with the air, is necessarily the 

 less ; and the entire surface is consequently cooled down to a temperature 



