168 PBOSEEPINA. 



conceivable to me by imagining the continual and invisi 

 ble descent of lightning from electric cloud by a conduct- 

 ing rod, endowed with the power of softly splitting the 

 rod into two rods, each as thick as the original one. 

 Studying microscopically, we should then see the mole- 

 cules of copper, as we see the cells of the wood, dividing 

 and increasing, each one of them into two. But the visi- 

 ble result, and mechanical conditions of growth, would 

 still be the same as if the leaf actually sent down a new 

 root fibre ; and, more than this, the currents of accumulate 

 ing substance, marked by the grain of the wood, are, 1 

 think, quite plainly and absolutely those of streams flow- 

 ing only from the leaves downwards ; never from the 

 root up, nor of mere lateral increase. I must look over 

 all my drawings again, and at tree stems again, with more 

 separate study of the bark and pith in those museum sec- 

 tions, before I can assert this ; but there will be no real 

 difficulty in the investigation. If the increase of the 

 wood is lateral only, the currents round the knots will be 

 compressed at the sides, and open above and below ; but 

 if downwards, compressed above the knot and open below 

 it. The nature of the force itself, and the manner of its 

 ordinances in direction, remain, and must for ever remain, 

 inscrutable as our own passions, in the hand of the God of 

 all Spirits, and of all Flesh. 



" Drunk is each ridge, of thy cup drinking, 

 Each clod relenteth at thy dressing, 



