150 SPRING. 



pine may be divided into a series of tubes like those of 

 a pocket telescope, and there are always some parts in 

 which the division can be made with the greatest faci- 

 lity ; but whether those be the production of warm sum- 

 mers or protracted winters, has not been determined. 

 That the rings in pines do register the qualities of the 

 seasons, there is not the least doubt; and some very 

 useful conclusions might be drawn from a careful com- 

 parison of them with observations made at the places 

 where they grow. 



That, however, is a work of time, and so are 

 many of the desiderata that have to be supplied before 

 we can settle the curious question as to why of two 

 plants, that are in many respects like each other, the one 

 should shed its leaves and the other be an evergreen. 

 The fruit, as well as the leaves, of the evergreens, at 

 least the greater part of them, appear to have the same 

 power of resisting the cold as the leaves ; and the boles 

 of them are also less liable to be covered with parasi- 

 tical plants. All vegetable substances, indeed, when 

 they are in a state of decay, are apt to become covered 

 with other vegetable substances, and the dead bark of 

 pines, when exposed to damp, is encrusted with lichens; 

 but they are by no means so common as on deciduous 

 trees. There is very rarely moss upon a yew or a 

 juniper, in those situations where the latter plant will 

 thrive. 



Though we cannot completely understand the phy- 

 siology of that part of the vegetable kingdom, we can 

 see some important uses of evergreens in the general 

 economy of nature. As has been said, they lessen the 

 violence of the winds which, when the herbaceous 



