From Charles H. Ham, Mind and Hand, 1886:

Nothing stimulates and quickens the intellect more than the use of mechanical tools. The boy who begins to construct things is compelled at once to begin to think, deliberate, reason, and conclude. As he proceeds he is brought in contact with powerful natural forces. If he would control, direct, and apply these forces he must first master the laws by which they are governed; He must investigate the causes of the phenomena of matter, and it will be strange if from this he is not also led to a study of the phenomena of mind. At the very threshold of practical mechanics a thirst for wisdom is engendered, and the student is irresistibly impelled to investigate the mysteries of philosophy. Thus the training of the eye and the hand reacts upon the brain stimulating it to excursions into the realm of scientific discovery in search of facts to be applied in practical forms at the bench and the anvil.