806 Modern Improvements in Horticulture, 



natural climates, by a difference in the consistence of their 

 sap, elasticity of their fibrous structure, or by that particular 

 state of growth, in which they are when assailed by the frost. 



Plants having a resinous, gummous, or inspissated sap, (the 

 state of that of almost all our deciduous trees during winter,) 

 seldom suffer from frost ; but those whose growth is caused by 

 the fluidity of their juice, or when it happens to be so, either 

 from its nature, or warmth of the air, and of whatever climate 

 they may be natives, they invariably suffer. The process of 

 hardening plants is by moving them gradually, and perhaps at 

 first only annually, from a warmer to a colder place, to pre- 

 pare them for the winter's frost, by keeping them as dry as 

 possible, and out of the sun's rays^, by giving them the driest 

 soil and situation during the cold months, and by reducing the 

 coverings (if coverings have been first used), till they can be 

 entirely left off. Seeds, grafts, or cuttings from these, will, it 

 is likely, be hardier than the parent ; so that in course of a few 

 years, a progeny may be reared able to bear our severest winters. 



A project for obtaining an increased degree of the sun's heat 

 has lately been practised, which may be mentioned : dark co- 

 lours absorb more of the sun's heat than others, therefore, fruit 

 walls have been painted, or rather stained with a black colour, 

 by which their heat is raised an extra ten degrees, which is a 

 material advantage if it could be had when most wanted ; and 

 if only when frosty nights may be expected it could be so ar- 

 rested as to resist the fatal chills of the night air, then it would 

 be a valuable protection. But it has been observed by a gen- 

 tleman-t* well skilled in meteorology, that the extra heat gained 

 in the day will be all radiated off before the return of morning ; 

 in which case, the additional excitement of the day will only 

 subject the trees to a more severe assault from the frost of 

 night. Those who have tried the plan, however, speak fa- 

 vourably of its effects, and especially as it kills the eggs and 

 frees the wall from insects. 



We have now gone over the subject as proposed, have taken 

 a hasty view of the early history of gardening, the gradual in- 

 troduction and improvement of it in Britain, together with a 



♦ Because, if the youngest shoots have been sufficiently ripened previously, thd 

 sun's heat in the autumn tends to liquefy the sap, and renders plants more suscep- 

 tible of injury from frost. 



t^F. Daniel, Esq; 



