On the other hand, within the tropics the means of existence are lavishly bestowed, the stimulus of animal food is not required, while the earth yields its vegetable productions in abundance; but in these regions, no strong motive stimulating to active exertion, the mental powers become enfeebled, and all those vices inseparable from habitual indolence are engendered. It is in the temperate regions, where nature is not lavish, but liberal, and yet requires the hand of labour and the head of thought, that the human race is presented to us in its highest form, whether bodily or mentally considered. It is in such regions that arts attain to perfection; that science walks hand in hand with religion. A thousand necessities urge to exertion and enterprise, and these are followed by a due reward.
Thus, then, are organic bodies, plants, the lower animals, and man, affected by atmospheric temperature; but man has called in heat, artificially produced, if we may use the word in a certain sense, to his aid. Without heat, ore could not be smelted, or instruments of metal made; glass and earthenware could not be manufactured; houses could neither be built, nor furnished with articles of utility; the operations of agriculture could not be successively carried on, nor ships built, nor steam engines or machinery be constructed, nor could man clothe himself or cook his food. In short, were it to please the Almighty to suspend the laws of caloric, man would be rendered at once helpless, and his senses useless; he must necessarily become a completely altered being, granting even that his continuance as a species upon the face of the earth were guaranteed.
With what wisdom, then, are the laws of the Almighty framed! How happily do they all conjoin to fit this world for the exercise of our senses and our reason! Yet, how mysterious they are! We know not even what light and caloric really are; they are incomprehensible, and yet we experience their influence, and daily test their laws. Who, then, can wonder that the fall of man, the decrees of God, the advent of Christ, his Divine and human nature conjoined, his death as an atonement of inestimable value, his intercession for all who come to him with faith, and the sanctification of the Holy Spirit, are each and all mysteries? "Canst thou by searching find out God?" Yet the believer knows _that_ God to be his Father and his Friend; he walks by faith and not by sight, "by faith of Jesus Christ unto all and upon all them that believe," and are "justified freely by his grace through the redemption that is in Christ Jesus." When we reflect upon the mysteries of nature, let us also think upon the mysteries of grace; let the consciousness of our own ignorance lead us to throw aside presumption, and trust to the words dictated by Him, to whom all mysteries are open, and whose wisdom and goodness have no bounds.