On the Cost of Horse-poiuer. 467 



of the horses of the farm the cost of the ploughing done by them 

 at Chester would not have been less than that at which, according 

 to the " Report," it was accomplished by Mr. Fowler's steam- 

 plough may be questioned. I am inclined to think it would. 

 A nice comparison of the two, to determine a difference of this 

 kind, is, however, quite beside the agricultural bearings of the 

 subject. Mr. Baker, of Writtle, expresses his belief above, that 

 even thrashing can be done as cheaply by horse-power as by 

 locomotive steam-engines ; but that does not hinder him from 

 employing the latter in order to the speedy accomplishment of 

 the work, and the setting free his horses for other employment. 

 The superiority of steam-power for such purposes is so great 

 that no one now is curious to inquire into the question of exact 

 comparative expense. And so it will be with steam-power 

 applied to cultivation. It will be applicable at the overcrowded 

 seasons of horse labour. A much smaller number of horses kept 

 throughout the year will suffice for the annual work of the farm 

 when a portion of the labour of the spring and autumn months 

 can be thus taken from them. And a direct advantage of this 

 kind, added to the indirect advantages of the deeper and more 

 thorough tillage which steam-power can effect, will ensure its 

 ultimate adoption, " altogether irrespectively of narrow differences 

 of cost per acre." 



Streatley, Reading, Dec. 1858. 



XX. — On the Structure of Roots. By Professor Henfeey, 

 F.R.S., &c. 



When we undertake a general examination of any subject relating 

 to plants, whether it be a scientific inquiry into the laws of their 

 growth, or a practical discussion of the economic value of their 

 products, we are naturally led to make a certain arrangement and 

 distribution of our questions. Such arrangements are forced 

 upon us by the diversity of character of the parts of the plants 

 themselves, and by the diversity of the products and of the means 

 by which additional amounts of their products are obtained. 

 Even if we confine ourselves to the comparatively limited, although 

 most important, gi'oup of plants with which the agricultural com- 

 munities of climates like our own are concerned, we shall derive 

 great advantage from a systematic method of research ; and if we 

 take care to keep this in its proper position, as an instrument, 

 and not as the object of our work, it will be found to facilitate the 

 explanations of our results when we attempt to draw them up in 



