ly Lindlei/s Theory of Horticulture, ^SS 



lation, and thus the health. Alpines, heaths, and most New Hol- 

 land plants will not do well without this motion of the air. He 

 also notices the necessity of keeping the house close at the time 

 of setting vines ; the injuries done by too much ventilation; the 

 opinions of Mr. Knight on that subject; and the success of Mr. 

 Ward in growing plants in confined glass cases, without any 

 ventilation. None of the plant cases in our quarter, nor any we 

 have heard of about Edinburgh, (though Orchidese, and other 

 plants naturally growing in close confined places, will do well 

 in them,) seem to warrant the opinion, that plants in general will 

 thrive as well without any ventilation as with a moderate portion. 

 Some of our best grape-growers allow that a good deal of air is 

 necessary, when the grapes begin to swell, to strengthen the 

 footstalk and prevent shriveling ; others are no doubt of opinion, 

 that shriveling proceeds from a failing of vigour at the root, or 

 too much divesting of the lateral foliage above the bunches ; 

 but there may be good reasons given for both opinions, and 

 perhaps both are causes. The bad effects of air in drying may 

 be greatly helped by the shallow zinc pans of Mr. Rogers, jun., 

 where hot-water pipes are used ; or by getting the tile covers of 

 the flue cast with hollow panels, to hold water for evaporation ; 

 where these are not used,* copious and frequent sprinkling of 

 water should be resorted to. In confined places, the oxygen 

 and hydrogen may be supplied by the water, and the carbon by 

 the decomposing substances in the soil ; but a renewal of the air 

 may be needed for a supply of nitrogen ; and as the rays of the 

 sun may be separated into light, heat, colour, and chemical rays, 

 as all these, and the electrical state of the atmosphere, may 

 be affected in ways we cannot yet account for, by screens inter- 

 posed, and may affect vegetation and maturation more than we 

 are yet aware of, we should be cautious in giving or withholding 

 air, and guard ourselves well by experience. Light is generally 

 believed to be the most necessary, in maturation of the fruit; 

 and the most transparent screens, and best reflecting walls, as 

 white or polished surfaces, should be used for this purpose, till 

 farther experience may lead us to modify our opinions. Should 

 electricity be found beneficial, glass and wood will be bad mate- 

 rials, being bad conductors ; metal and oiled paper or talc might 

 be better. 



On the next sections, of the Germination and Matur- 

 ation of Seeds, Dr. Lindley quotes Berzelius as to the pro- 

 portions of carbon in gum and starch ; and makes the gum 

 to have the larger proportion of carbon and the less of 

 water. M. Schultze, in the Prize Essay given in to the Aca- 

 demy of Sciences, on the circulation of the latex, or blood of 

 the plant, considers gum as the first result of the fixation of 

 carbon with hydrogen and oxj^gen ; and that sugar, starch, and 

 fibrine are farther degrees of fixation, containing more carbon. 



