atting on a Mass of loose Stones. 51 



and into the other very coarse sand mixed with small gravel, 

 such as is found in beds of rivers, is put for plunging the 

 pots, in order to ascertain if any advantage will result from 

 using such substances. 



Rotten dung may answer as well as rotten leaves, only there 

 can exist no necessity in this case for using nutritious sub- 

 stances. But I intend to request the gardener at Castle 

 Semple to plant this season, by way of experiment, about a 

 dozen of fruiting pines in pots, with two rows of holes in the 

 sides, about 3 or 5 in. from the edges, and to plunge them in 

 properly prepared soil. I shall also mention well rotted cow- 

 dung. The holes will allow a part of the roots to run out of 

 the pots, and derive nourishment from the material in which 

 the pots are plunged ; and as these pines will be grown in the 

 same pit with those in earth above mentioned, and with others 

 in pots without holes in their sides, an opportunity will be 

 afforded of observing; what advantage would arise from such 

 a mode of treatment. 



Sawdust I have long used in frames for striking cuttings. 

 It was employed in one of the first steam plant-stoves that I 

 erected : but an immense number of small red worms bred 

 among the dust ; occasioned, I suppose, by too much moisture 

 getting through the joints of the pavement which covered the 

 bed of stones, in consequence of the joints not having been 

 checked upon each other, and only being pointed with com- 

 mon lime : the use of it was therefore discontinued. I have 

 no doubt that ashes would do very well, but I cannot speak 

 of them from experience. Were it found convenient to use 

 them, it would give the bed a more cleanly and finished 

 appearance to be covered with a thin layer of gravel or small 

 pebbles. After all, perhaps a light gravelly soil will be found 

 to be the most suitable, as it will allow the moisture received 

 from watering the pines over-head in the summer months to 

 drain off readily : but it would not be proper to plunge in 

 this such pots as have holes in the sides. 



I think this method of heating by steam is capable of im- 

 provement, which, I doubt not, it will receive when it comes 

 under the management of gardeners of experience. I am 

 confident that by this means pine-apples and melons, or ten- 

 der exotic plants for ornament, may be grown at any place 

 where fuel can be procured, although neither tanners' bark 

 nor dung is to be got ; nor have I any doubt that it could be 

 applied with success, under some modifications, to the different 

 kinds of forcing. 



I am, Sir, &c. 

 Edinburgh, July 24. 1829. John Hay. 



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