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 atmoiphere ; and the lower ones forming the radicles 

 of it, which are abibrbent 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 flrangulated with a wire 

 or cut off ; or otherwife when it is fupplied more abundantly 

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

 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 gokSen- 

 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 irigraftment confifls in this, 

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

 many parents ; when io many different (cions are ingrafted on 

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

 two kinds of anther-dud previous to its application to the flig- 

 ma of flowers might not produce a threefold mule partaking of 

 the likenefs of both the males ? 



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

 common apprehenfion, the patient reader will excufe a more 

 prolix inveftigation. The attraction of all matter to the centres 

 of the planets, or of the fun, is termed gravitation, tha f of par- 

 ticular bodies to each other is generally called chemical affinity j 

 to which the attraclions belonging to electricity and magnetilm 

 appear to be allied. 



In thefe latter kinds of attraclion two circum (lances feem to 

 be required, firit, the power to attral poflefled by one oi the 

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

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

 to poflTefb a fpecific tendency ro unite with iron ; and the iron 

 may be faid to poiTefs 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 reftor- 

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

 united with the magnet, becaufe no other metal will approach 

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

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

 with a light draw, or hair, and the flraw or hair to poflefs a 



fpecific 



