374 Retrospective Criticism. 



probably an error in the periods may have occurred, I wish Mr. Appleby 

 had given some information respecting the size, shape, and dimensions of his 

 boiler. The weight, 80 lb. " with taps included," does not convey any idea 

 of either ; neither does he give the size of his house. These particidars 

 might be of considerable advantage to any person wishing to pursue the same 

 mode of treating their plants. 



I therefore take the liberty of giving you the manner by which I create 

 a humid atmosphere for my orchideous epiphytes ; fully aware of the advan- 

 tage they derive from this system, in every instance save one ; and in that 

 particular I must take the liberty of differing from Mr. Appleby. I do so 

 with great diffidence, and with the hope that he may be induced, by some 

 future remarks on this subject, to enable me to overcome the only difficulty 

 and imperfection which I conceive exists in the admission of steam. 



To quote Mr. Appleby's words, " The most delicate flowers are not in- 

 jured, nor their duration shortened." I unfortunately have found that 

 several flower-buds have been so injured as to turn quite yellow and sickly, 

 and drop off a few days before they ought to have expanded. This has 

 occurred with the catasetums and cattleyas, and several of the oncidiums 

 have had " their periods of duration shortened." The same injury has 

 occurred to some stove plants, which I introduced amongst the epiphytes. 

 This I now remedy by removing the flowering plants at a proper period to a 

 dry house. On the other hand, there are several which do not appear to be 

 affected by it. At the same time that I regret this, I am well repaid by the 

 rapid and luxuriant growth of the plants, and by the number of pseudo-bulbs 

 they have and are now forming. Those plants which two years ago were 

 small, weak, and sickly, have now become large and healthy, and have thrown 

 up three, four, and five shoots ; and next year many of them will be what 

 may be called fine specimens. Added to the modified steam they receive during 

 a considerable portion of the night, particularly in warm weather, which may 

 be said to be analogous, in a great measure, to their heavy native nightly dews, 

 I frequently syringe overhead with tepid water, generally twice a week, and 

 sometimes oftener. This I am induced to do, as I find the material in which 

 they are potted is not much affected by the steam, being only superficially moist. 



My plants are placed on platforms of white Yorkshire flags, and the pots 

 are packed round with flakes of fresh moss, which gives the house a very 

 pleasing appearance, and retains a great deal of moisture. The flags also 

 absorb much of the water used in syringing, and keep up a constant humidity, 

 particularly in warm weather, by gentle evaporation, which is grateful to the 

 plants, I would recommend Mr. Appleby to introduce a plant of the Coffea 

 occidentalis (Tetramerium odoratissimum Sjweng.) into his house ; it seems to 

 thrive particularly well in that atmosphere, and its rich and luxuriant dark 

 green foliage is highly ornamental. 



It is now three years since I put up a steam boiler, attaclied to a small 

 pine-house, and having experienced the decided advantage derived from a 

 humid atmosphere, in swelling off the grapes and pines, as well as the healthy 

 appearance, cleanliness, and growth of the few stove-plants in the house, 1 

 placed a boiler to every house except the green-house. In February, 1838, 

 for the same reason given by Mr, Appleby, to create a moist atmosphere in 

 the orchideous house, which is 22 ft, long, ] 2 ft, wide, I attached a boiler to it. 



The boiler is of metal 2 ft, 6 in. long, by 2 ft. wide, 1 ft. 3 in. deep, and ^ in. 

 thick, inside measure ; and it diminishes 2 in. from top to bottom on the four 

 sides. The flanche round the boiler projects 2i in. ; the cover is flat, and 

 i in. thick, with the usual holes, which I drill in the situations best suited for 

 the safety-valve, steam-pipe, supply-pipe, and gauge-cocks. There is also a 

 hole cast in the centre of the lid Sin, by 4 in,, oval in form, to clean out the 

 boiler when requisite. The cover is fastened on the flanche of the boiler by 

 bolts and nuts, and the joining made good with iron cement, composed of 

 borings of metal, sulphur, and saltpetre. This makes the boiler steam-tight. 



The boiler is set over the fire which heats the house (as I continue to 



