HAWTHORN. 



153 



as the earth is charged with electric fimds, as vegetable 

 substances are known conductors of it, that the bark, by its 

 fermentation, not only generates heat, but serves as a mean 

 to produce out of the earth an atmosphere for the plants, 

 sufficient, with such atmospheric air as will Bnd admission, 

 to supply the quantity exhausted by the daily rarefaction 

 occasioned by the sun's heat. 



" A green-house has been used upon this construction in 

 this state, without having had the least occasion of being 

 heated by fire. The plants in the spring were remarkably 

 thrifty ; tropical fruit ripened in it during the winter, and 

 young fruit formed on the trees. It required no other care, 

 than now and then watering the plants, and shutting the 

 windows as soon as the sun left them." 



With respect to the management of plants in green- 

 houses, it is recommended occasionally to open the mould 

 in which they are set, to scatter a little fresh earth on the 

 pots, and over this to lay a little dung. It will also be ad- 

 visable to water them when the leaves begin to curl or 

 wither, and to pluck off such as are decayed ; but these 

 operations should not be too frequently repeated. 



" Some people," says M'Mahon, " are desirous of keep- 

 ing out their plants as long as possible ; this is very right, 

 but it ought not to be extended to too hazardous aperiod ; for 

 one night's frost would cause the leaves to lose their fine 

 green colour, which perhaps might not be restored during 

 the whole winter ; and, if any v*^ay severe, serious injury 

 might be sustained. 



" If the windows and doors are kept open day and night, 

 as long as there is safety in so doing, the plants will be 

 nearly as well off as in the open air, and no danger is en- 

 countered : the mere difference of five or six days in the 

 taking in of the plants will ensure safety ; but, on the other 

 hand, it is not right to be too precipitate in housing them, 

 before the common appearance of the weather indicates 

 the necessity." 



HAWTHORN, — CratcBcjus. — There are a great many 

 species of this genus of plants, {see Hedge,) of which the 

 oxjjcantha^ or English hawthorn, as it is commonly named 

 in the United States, is most generally cultivated for the 

 purpose of forming hedges. The manner of raising the 

 thorn quicks is as follows : — 



Collect your seeds in autumn, mix them with equal 

 quantities of light, sandy earth, and lay them in that state on 

 the surface of a dry spot of ground in your best enclosed 



