From Dedication: "My Lord, In submitting this volume to the public under your Lordship-s auspices, I avail myself of the opportunity thus afforded me of expressing the deep sense which I entertain of the friendship and kindness with which your Lordship has so long honoured me.Although in these days, when Science constitutes the power and wealth of nations, and encircles the domestic hearth with its most substantial comforts, there is no risk of its votaries being either persecuted or neglected, yet the countenance of those to whom[vi] Providence has given rank and station will ever be one of the most powerful incitements to scientific enterprise, as well as one of its most legitimate rewards. Next to the satisfaction of cultivating Science, and thus laying up the only earthly treasure which we can carry along with us into a better state, is that of having encouraged and assisted others in the same beneficent labours. That your Lordship may long continue to enjoy these sources of happiness is the earnest prayer of,My Lord,Your Lordship's Most faithful and obedient servant, DAVID BREWSTER. St Leonards, St Andrews "