The Origin and Belations of the Curhoii Minerals. 2G1 



XVI. — The Origin and Relations of the CarTjon Minerals. 



BY J. S. NEWBERRY. 



Read February 6th, 1882. 



What are called the carbon minerals, — peat, lignite, coal, gra- 

 phite, asphalt, petroleum, etc., — are, properly speaking, not 

 minerals at all, as they arc organic substances, and have no 

 definite chemical composition or crystalline forms. They are, 

 in fact, chiefly the products or jDhases of a progressive and 

 inevitable change in plant-tissue, which, like all organic matter, 

 is an unstable compound and destined to decomposition. 



In virtue of a mysterious and inscrutable force which resides 

 in the microscopic embryo of the seed, a tree begins its growth. 

 For a brief interval, this growth is maintained by the prepared, 

 food stored in the cotyledons, and this suffices to produce and to 

 bring into functional activity some root-fibrils below and leaves 

 above, with which the independent and self-sustained life of the 

 individual begins. Henceforward, perhaps for a thousand years, 

 this life goes on, active in summer and dormant in winter, ab- 

 sorbing the sunlight as a motive power, which it controls and 

 guides Its instruments are the discriminating cells at the ex- 

 tremities of the root-fibrils, which search for, select and absorb 

 the crude aliment adapted to the needs of the plant to which 

 they belong, and the chlorophyll cells — the lungs and stomach 

 of the tree — in the leaves. During all the years of the growth 

 of the plant, these organs are mainly occupied in breaking the 

 strongly rivetted bonds that unite oxygen and carbon in car- 

 bonic acid ; appropriating the carbon and drawing off most of 

 the oxygen. In the end, if the tree is, e. g., a Sequoia, some hun- 

 dreds of tons of solid organized tissue have been raised into a 



