The dynamics of geology suggest problems of no ordinary interest, but our narrow limits forbid even a statement of them. MINERALOGY Is that branch of geology that treats of mineral substances, and teaches how to distinguish and classify them according to their properties. This is a wide field for investigation, and so fruitful that the temptation to linger in it is strong. Mining and work with the products of the mines engage the industry of so many that it would be especially pleasant to study with them a subject of such general interest. We relinquish that privilege, in order to state two or three things that seem thoroughly established by what is found written in the book of nature, and are in perfect accord with God’s later scriptures, the Bible, when rightly interpreted. 1. The first fact is the great age of the earth. Processes are plainly indicated that must have required not only thousands, but millions of years for our planet, before man, made in the image of God, entered it as the theater of his responsible activities. The facts of the carboniferous[4] period alone discredit, and utterly overthrow the theory which limits the days of creation to six of twenty-four hours each. The Bible gives the order of the successive creations, but does not fix the age of the things created. The word translated day often means an _age_ or an indefinite number of years, as is seen by referring to the places where it is found. Give it this well established meaning in the first chapter of Genesis, and all is plain. There was time for millions of races of inferior creatures to live and die before the divine plans and works were consummated, and the earth became a suitable abode for the human race. 2. The second great fact is that all things were made on a plan, and in some connection. There are no isolated objects or superfluous parts in the physical world. The number may be countless, and the forms given them reveal an endless variety, but each has its connections, and all the parts are necessary to a perfect whole. 3. Another lesson is learned from the mute witnesses, which is that, while a long succession of races of animals, for which the earth, in its different stages of progress was a fit abode, existed, each higher in rank than its predecessor, the several races had distinctive characteristics, as the _radiates_, _mollusks_, _articulates_, and _vertebrates_. A lower species, when its purpose is served, becomes extinct, and is succeeded by a higher. CHEMISTRY,