136 ASCENT OF SAP IN LOFTY TREES. 



Some analogy seems to exist between the ascent 

 of the bar within the tube of the helix coil and 

 the ascent of sap in the tubular pores of trees ; 

 and also of fluids in lamp-wicks, porous sponges, 

 sugar, &c., in the manner denoted " capillary 

 attraction." ' . 



The ascent of sap against the action of gravita- 

 tion to the height of three hundred feet in the 

 California cedars, may be thus explained. The 

 force of the absorbent capillary action of sap even 

 in a humble pumpkin, or squash, has been exper- 

 imentally proved, at the State Agricultural Col- 

 lege, Amherst, Mass., to be sufficiently powerful 

 to upheave a weight of several thousand pounds, 

 during its growth. 



The phenomenon of the elasticity of steel springs 

 and of woody fibres admits of explanation on this 

 principle of diamagnetic molecular action ; which 

 allows of the partial sliding of the particles on one 

 another with a retraction, like the drawing back 

 of the iron bar with the appended weight. 



The considerable range of action of the diamag- 

 netic currents, as compared with the polar mag- 

 netic action, has been resorted to by ingenious 

 experimenters for utilizing electro-motive power. 

 To test the efficiency of this plan, the Congress 

 of the United States was induced to appropriate 

 twenty thousand dollars for an experimental ma- 

 chine devised by Dr. Page, thirty years ago. To 

 produce a direct rotary motion, he used, instead of 



