CHAPTER VIII. 



THE FRUIT AND FOREST TREES. 



OF THE COMPOSITION OF THE ASH OF FRUIT AND FOREST TREES. WITH REMARKS ON THE DISTRIBUTION OF 

 THE ELEMENTS IN THE PARTS AND ORGANS COMPOSING THEM. 



The fact ascertained by Saussure, that plants require a certain amount of inorganic matter 

 for the perfection of their foliage and seed, has made the subject of inquiries into the 

 chemical constitution of vegetables extremely interesting and important. This fact in- 

 creases in interest in consequence of another fact well ascertained, namely, that plants not 

 only require a certain amount of matter usually denominated inorganic, but that this amount 

 differs essentially with the different families, and even with the different species of plants. 

 So it appears too that different parts and organs of the same plant require different amounts 

 of the elements composing the ash. The seed and fruit, the root and trunk, the leaves 

 and branches, each secure for themselves different quantities of what we may call the solid 

 food. Even the seasons of the year are marked in the life of the vegetable by different 

 proportions of inorganic matter. The vegetable system goes on accumulating inorganic 

 matter slowly, until it has collected a store of food for future consumption. 



I shall not attempt to post up what is known upon the subject before us ; my object being 

 to state generally the results of my investigations, and those which have been made by my 

 assistant during the Survey. The analysis of the ash of forest and fruit trees has been 

 prosecuted during a part of the last three years : more than a year of constant labor by 

 myself and assistant has been thus bestowed. The analyses, it is proper to say, have not 

 been made with the sole object of ascertaining the elements, or the proportion of elements, 

 which enter into the constitution of plants ; but a higher object has been in view, namely, 

 the determination of the law of distribution of the elements. That a law should conlrol 

 their distribution appeared to be highly probable from analogy ; and it may be inferred 

 that the ends of existence are better subserved under its control, than if their distribution 

 had been left to accident. 



I now proceed to state that it was early conceived that the inorganic matter, in the 

 growth of plants, was constantly determined by two movements : first, an upward move- 

 ment, which really constitutes the circulation ; and, secondly, an outward movement, by 

 which the matters are transferred from the centre to the circumference, which movement 

 results in a diminution of the inorganic matter of the interior, an effect which constantly 



