398 MR. R. RIGG'S EXPERIMENTS ON NITROGEN IN VEGETABLE PRODUCTS. 



Table V. 



Thus, for instance, the nitrogen in the satin wood may be considered almost inap- 

 preciable ; and the same may be said of the residual in the Malabar teak, the nitrogen 

 being also small in this timber. In Dantzic and English oak the quantity of nitrogen 

 and residual are both very small. In American birch the nitrogen and residual are 

 in large quantities, and, as is well known, this timber decays very quickly. 



But it is not enough for us to find a difference in the proportionate quantity of ni- 

 trogen in the different parts of the same plant or tree ; we must also observe that the 

 quantity appears to be proportional to the functions which the parts of the plants 

 have to perform in vegetation. For instance, if the agency of any part of the plant 

 be great in the scale of vegetable physiology, so is the quantity of nitrogen, and vice 

 versd. So apparent is this, and so universal is the operation of this law over the 

 whole sphere of inquiry in which I have been engaged, that we might almost con- 

 sider this element, when coupled with the residual, to be the moving agent, acting 

 under the influence of the living principle of the plant, and moulding into shape the 

 other elements. We have this beautifully instanced in the chemical constitution of 

 the different parts of wheat, barley, oats, common grass, turnips, cabbages, carrots, 

 potatoes, &c., found by subjecting their various parts to analysis at different periods 

 of their growth (See Table VI.). For by thus subjecting the different parts of the 

 same plant to analysis at different periods of growth, we acquire much valuable in- 

 formation upon vegetation generally, and respecting the influence of nitrogen and re- 

 sidual in particular. 



