234 



PREFACE. 



Arborum, why endeavor to increafe their num- 

 ber ? Are there not idle people enough already ^ 

 What fignities whether fuch a plant be in blow or 

 in leaf at the fame time with fome others •, or 

 when fuch a bird comes or goes; fings or is 

 filent ? If we hear the bird fing, and know for 

 what purpofes the plant is ufeful, we know all 

 that is neceflary ; every thing beyond that is but 

 the wilh, or rather dream of enthufiafm, which 

 wants to give an air of importance to its favo- 

 rite fubjedt. This perhaps may be faid by fome ; 

 but the fame way of reafoning applied to other 

 things will Ihew, that it may pofTibly be wrong. 

 For inftance, the fea fwells twice in 24 hours, 

 and the moon pafles thro' the meridian circle as 

 often in the fame time. Now fhould it be faid, 

 that if we know each of thefe truths feparately 

 it is enough ; and that to know farther what re- 

 lation in point of time one of thefe phenomena 

 has to the other, is nothing to the purpofe ; i 

 believe fuch an affertion would at this tirne ap- 

 pear abfurd, however it might have pafTed in ig* 

 norant ages. I think we may affert univerfally, 

 that whenever two things, however difparate in 

 their nature, conftantly accompany one another, 

 they are both aduated and influenced by the 

 fame caufe. Now that caufe may probably ope- 

 rate on other things that lye within the reach of 

 our powers, and depend on our determination. 

 Thus that conftitution of the air, which caufes 

 the cuckow to appear about the time, when the 

 ficT-tree puts forth its fruit, may indicate the pro- 

 pcreft feafon to fow fome of our moil ufeful feeds, 

 or do fome other work which it imports us to do 

 at a right time j and that time may not be ac- 

 cording 



