The point on which the Duke of Argyll lays most stress, is, that proofs of Mind everywhere meet us in Nature, and are more especially manifest wherever we find "contrivance" or "beauty." He maintains that this indicates the constant supervision and direct interference of the Creator, and cannot possibly be explained by the unassisted action of any combination of laws. Now, Mr. Darwin's work has for its main object, to show, that all the phenomena of living things,--all their wonderful organs and complicated structures, their infinite variety of form, size, and colour, their intricate and involved relations to each other,--may have been produced by the action of a few general laws of the simplest kind, laws which are in most cases mere statements of admitted facts. The chief of these laws or facts are the following:-- 1. _The Law of Multiplication in Geometrical Progression._--All organized beings have enormous powers of multiplication. Even man, who increases slower than all other animals, could under the most favourable circumstances double his numbers every fifteen years, or a hundred-fold in a century. Many animals and plants could increase their numbers from ten to a thousand-fold every year. 2. _The Law of Limited Populations._--The number of living individuals of each species in any country, or in the whole globe, is practically stationary; whence it follows that the whole of this enormous increase must die off almost as fast as produced, except only those individuals for whom room is made by the death of parents. As a simple but striking example, take an oak forest. Every oak will drop annually thousands or millions of acorns, but till an old tree falls, not one of these millions can grow up into an oak. They must die at various stages of growth. 3. _The Law of Heredity, or Likeness of Offspring to their Parents._--This is a universal, but not an absolute law. All creatures resemble their parents in a high degree, and in the majority of cases very accurately; so that even individual peculiarities, of whatever kind, in the parents, are almost always transmitted to some of the offspring. 4. _The Law of Variation._--This is fully expressed by the lines:-- "No being on this earthly ball, Is like another, all in all." Offspring resemble their parents very much, but not wholly--each being possesses its individuality. This "variation" itself varies in amount, but it is always present, not only in the whole being, but in every part of every being. Every organ, every character, every feeling is individual; that is to say, _varies_ from the same organ, character, or feeling in every other individual. 5. _The Law of unceasing Change of Physical Conditions upon the Surface of the Earth._--Geology shows us that this change has always gone on in times past, and we also know that it is now everywhere going on.