2. There is the absolutely certain sequence of physical causes and effects, or antecedents and consequents, which we call laws of nature, which vary not one hair’s breadth from their ordained order in obedience to the mandates of our will, but which, by observing and mastering the principle of that order, we can use for the accomplishment of our ends. These are our tools to work with. A thousand subtle laws are concerned in every process of the husbandman’s toils. On a large scale and in the long run the question of his success depends absolutely on his comprehension and observance of those laws. The progress of man’s knowledge of nature is really a progress in the mastery of the variable element in the problem of his labour. A thousand accidents, which baffle the ignorant and careless husbandman, obey the control of the intelligent and strenuous. The order is rigid. There is an awful sternness in its certainty; but it grows benign to him who has mastered its secret. It obeys him as a servant, it helps him as a friend; and the certainty with which he can calculate its action is one essential element of its friendliness. If he could not weigh the materials and measure the forces which are constantly around him, if he could not count on their known relations and actions with the same calm certainty with which he expects the sunrise to light him to his daily toils, his life would be one of miserable dependence; he would live the serf of nature, and not her king. It is the unalterable fixity of relations and forces which God has given him the power to discover and to employ, which constitutes the royalty of his rule over nature; if that be destroyed or shaken, his crown rolls in the dust. The constancy of the relations and forces of the universe, their impassibility to the force which man’s will can bring to bear upon them, of which his husbandry gives him full experience, is an essential element, perhaps we might say _the_ essential element, in that higher culture which they offer to his spirit; it is this which makes the life of even the workman something higher than a lottery, and the toils of earth an education for the works and the joys of heaven.