Microscopical Essays. 



$53 



tion to the ftru&ure of plants; to this, among other can fes, we 

 may alfo afcribe the inftability and fluctuation of the different 

 theories on the principles of vegetation. We are, however, fo 

 little acquainted with the Heps which Providence takes to lead in- 

 telle&ual, but free agents, to the knowledge of truth, and the 

 various difficulties, errors, and prejudices that muff be removed 

 before it can mine in it's native colours, that it is our duty to en- 

 courage every humble effort towards the advancement of Fcience, 

 that thus we may co-operate with our Creator and Redeemer in 

 promoting that vaft plan to which all things are now converging, 

 the bringing all his creatures to a flate of truth, goodnefs, and 

 confequent happinefs, an end worthy of the belt and wifeft of 

 beings.* 



As Dr. Hill is the firft writer who has treated this part of 

 natural hiftory in an orderly and fcientific manner, I (hall ufe the 

 names he has adopted for characterizing the different parts of 

 trees, &c. which are, 1. the rind; 2. the bark; 3. the blea ; 

 4. the wood; 5. the corona or circle of propagation; 6. the 

 pith. Thefe are placed immediately within or under one ano- 

 ther; they are the efiential parts upon which the firength of the 

 tree depends : in, among, and between thefe, the various veffels 

 are placed, which nourifh the whole, and maintain and carry on 

 the vegetation of the tree, and from which it obtains it's peculiar 

 qualities and virtues. Thefe veffels are of five kinds. 



Juice 



* See the Bifliop of Exeter's Ssrmon before the Society for the Propagation of the 

 Gofpel. 



