420 GENERATION. Sect. XXXIX. 8. 6, 



of the trunk of the tree ; the upper ones forming the plumula 

 of the new bud, which is its leaf or lungs to acquire oxygen 

 from the atmofphere •, and the lower ones forming the radicles 

 of it, which are abforbent veiTels to acquire nutriment from 

 the earth. 



Secondly, that every part of the caudex of an ingrafted tree, 

 and confequently of all trees, can generate or produce a new 

 plumula, when the upper part of it is ftrangulated with a wire 

 or cut off *, or otherwife when it is fupplied more abundantly 

 with nutriment, ventilation, and light. And that each of thefe 

 new buds thus produced refembles that part of the flock in com- 

 pound trees, where it arifes. Thus in the triple tree above 

 mentioned a bud from the upper part of the long caudexes, 

 which form the filaments of the bark, would become a golden- 

 pippin branch, a bud from the middle part of them would 

 become a nonpareil branch, and a bud from the lower part a 

 crab branch, 



Thirdly, another wonderful property of this lateral mule 

 progeny of trees compounded by ingraftment confifts in this, 

 that the new mule may confift of parts from three or four or 

 many parents ; when fo many different fcions are ingrafted on 

 each other, whence a queftion may arife, whether a mixture of 

 two kinds of anther-dull previous to its application to the ftigma 

 of flowers might not produce a threefold mule partaking o£ the 

 likenefs of both the males ? 



6. On this nice fubject of reproduction, fo far removed from 

 common apprehenfion, the patient reader will excufe a more 

 prolix investigation. The attraction of all matter to the centres 

 of the planets, or of the fun, is termed gravitation, that of par- 

 ticular bodies to each other is generally called chemical affinity ; 

 to which the attractions belonging to electricity and magnetiim 

 appear to be allied. 



In thefe 'latter kinds of attraction two circumftances feem to 

 be required, firft, the power to attract poflefled by one of the 

 bodies, and feconrily, the aptitude to be attracted poflefled by 

 the other. Thus when a magnet attracts iron, it may be faid 

 to porTefs a fpecific tendency to unite with iron ; and the iron 

 may be faid to poffefs a fpecific aptitude to be united with the 

 magnet. The former appears to refide in the magnet, becaufe 

 it can be deprived of its attractive power, which can alfo be reftorr- 

 ed to it. And the iron appears to poffefs a fpecific aptitude to be 

 unite'd with the magnet, becaufe no other metal will approach 

 it. In the fame manner a rubbed glafs tube or a rubbed ftick 

 of fealing wax may be faid to poffefs a fpecific tendency to unite 



ith a light ftraw, or hair, and die draw or hair to poffefs a 



fpecific 



