hy Lindlei/s Theory of Horticulture. 431 



however much by circumstances we may affect individuals for a 

 time. 



On the subject of the Colours of Plants, noticed by the 

 professor in this section, it has been said by chemists, in ana- 

 lysing plants, that in the red and deep colours acids are most 

 prevalent, and that in the green and light colours the alkalies 

 abound : and, having been formerly a very assiduous cultivator of 

 tulips, I have frequently tried the effects of the alkaline lime in 

 depriving what are called run or too highly coloured flowers 

 of their excess in colour ; and likewise the oxide of iron, an acid, 

 and the natural colouring matter of the soil, in producing colour 

 in those which were too light. We had few tulips too light in 

 the beds; this does not occur so frequently as too dark, and we 

 do not recollect of much success in our experiments this way; 

 but we have seen beds of tulips to come more than ordinarily 

 coloured, technically foul, when composts were used, owing to 

 ignorance, from ditches where oxide of iron was deposited, a 

 very common occurrence, especially in clayey soils ; and, though 

 the deposit in the ditch should be otherwise rich, it should never 

 be used where light-coloured flowers are wanted ; the effects pro- 

 duced from these deposits, however, would lead us to infer that 

 oxide of iron will produce more colour in flowers that are too 

 light. In our experiments with lime, the trials were more 

 frequent, and with more decided effect. We have had flowers 

 of Imperatrix florum, Bienfaite, and other flowers, so full of 

 colour as to be nearly selfs, and to which we applied lime in the 

 soil, come much paler even than their usual state of colour, 

 some of them nearly white : this alteration did not take place 

 till the year after applying the lime ; thus showing that the next 

 year's flower had been altered in the vessels that were to cover 

 the chromule of the next year, while yet in embryo in the root. 



The effects of heat and cold on plants are so minutely entered 

 into in the work before us, the effects of frost so minutely de- 

 scribed, both in this section and the one on atmospherical 

 temperature, and so great a range of temperatures from different 

 countries brought forward, that it cannot fail to be highly in- 

 teresting to all concerned in the cultivation of plants. 



On the next sections, of Moisture of the Soil and Watering, also 

 Atmospherical Moisture and Temperature, the causes and effects 

 of want of moisture in the air of houses are fully explained, and 

 to this and the able article in the Gardener'' & Magazine for June, 

 by Mr. Rogers, jun., little could be added. In the open air, 

 some situations, as the vicinity of woods and hills, by their 

 effects in electricity, are more productive of rains than others j 

 some kinds of stones, as trap, clay slate, &c., are more retentive 

 of moisture than quartz, silex, and others ; and soils from the 

 debris of these, as clayey from the former, are more retentive of 



F F 4) 



