NOTICES OF AUTHORS. 



The above facts must lead, we think, to the con- 

 clusion, that evaporation, or non-evaporation, of the 

 fluids, has, directly, a very considerable influence in 

 causing a shorter or longer extension of the shoot 

 betv/een the buds or leaves, and that the influence 

 of the cold of this evaporation is at most but of a 

 very secondary character. We would compare the 

 extending rudiments and matter of the young scion 

 to the slow flowing of a gelatinous fluid. In moist 

 air, the watery part is slowly evaporated, and the 

 drop extends into a long pendulous form. In dry 

 air, the water of solution is quickly evaporated, lon- 

 gitudinal extension ceases, and the pendant is thick- 

 er and shorter. The cold of evaporation may a 

 little affect the fluidity, but only in a very small de- 

 gree 



The causes of the elongation of vegetables are, 



* In proceeding further on in Sir Henry's volume, we have 

 noticed an excellent observation quoted from Du Hamel : " The 

 extension of the shoot is inversely as its induration, rapid while it 

 remains herbaceous, but slow as it is converted into wood. Hence 

 moisture and shade are the circumstances, of all others, the most 

 favourable to elongation, because they prevent induration or re- 

 tard it." Although quoting this, Sir Henry recurs to his old opi- 

 nions, and proceeds to observe, " Trees so circumstanced, push 

 upward to the light ; and from the warmth which their situation 

 affords, their stems being thin and slender in proportion to their 

 height, they are destitute of strength to resist the winds.'^ 



