[14] The unstratified are often called crystalline rocks, because they frequently have a glassy appearance, or contain regular crystals of certain mineral substances; often also igneous rocks, because they appear all to have been originally in a melted state, or to have been produced by fire.
[15] The reader is referred for more precise information to the author’s “Lectures,” pp. 377 to 390.
[16] By locally excellent, I mean those who are the best possible farmers of their own district and after their own way, but who would fail in other districts requiring other methods. To the possessor of agricultural principles the modifications required by difference of crop, soil, and climate, readily suggest themselves, where the mere practical man is bewildered, disheartened, and in despair.
[17] It is owing to this large quantity of saline and other inorganic matter that fermented leaves form too strong a dressing for flower borders, and that gardeners therefore generally mix them up into a compost.
[18] Though I have dwelt as long upon these interesting and, I believe, novel considerations, as the limits of this little work will permit, yet I must refer the reader for fuller details, and to perhaps a clearer exposition of the principles above advanced than I have here been able to give, to my “Lectures on Agricultural Chemistry and Geology.”
[19] See the author’s “Suggestions for Experiments in Practical Agriculture,” Nos. 1 & 2.
[20] The result of trials made on the mica slate and gneiss soils (see page 100) of the Duke of Atholl.
[22] Albumen is the name given by chemists to the white of the egg. A small quantity of this substance is present in every kind of grain. It is closely related to gluten.