LETTER XXI.•

NATURAL PHILOSOPHY.

MY DEAR M, There is one great subject of study for a rational and intelligent creature-the knowledge of God. There are two sources through which this knowledge is derived the material objects of creation, and the moral characters which occupy it. Sciences are valuable practically as they give perfection to art, and qualify us for the able discharge of the duties arising out of our temporal relations. As the food of an immortal spirit, they are valuable, as they aid us in the investigation of these two great departments of the knowledge of God.

Natural philosophy guides us in inquiries concerning the material objects of creation; mental and moral philosophy directs our study of the intelligent and accountable. The governing principles which constitute the essential wisdom of the one are exhibited in operation; and we are competent, as far as the restriction of our faculties and the disabilities of our physical frame allow, to trace their working, and comprehend their character and design. The governing principles of the other we are not able to observe in operation. Sin has perverted their legitimate working; and also depraved our judgment, so that it cannot deal with them aright. They are, therefore, revealed in verbal characters, in the word of inspiration.

The study of mathematics as applied both to number and extension; mechanics and chemistry in their divers applications within and without the terraqueous globe; physiology in its varieties, animal and vegetable, concentrate the truth elicited by the repeated and comparative examination of the works of God, and contain a fund of ascertained truths, which we apply on the principle of analogy for the acquisition of further knowledge.

History, general literature, language, geography so far as it assists history, aid our researches in the department of morals. Though they would never alone have guided us to truth, and without revelation would not have been as valuable as they now are, they yet confirm and illustrate, by example, the truths concerning morals which the Scriptures reveal.

We become truly intelligent, then, as our knowledge of these two great subjects is correct and comprehensive. When the restrictions which fetter their mental powers, and the darkness which obscures their vision, are no more-when the material and the moral shall both be displayed more fully, and the powers shall be cleared and quickened for their steady perceptionthe hosts of the redeemed will render the intelligent ascription of praise-"Great and marvellous are thy works, Lord God Almighty! just and true are all thy ways, thou King of saints." And the bliss of the contemplation, the luxury of increase in such knowledge, the delight of rendering praise, which is due to Him who hath made wonderful things without number, and done great things for them whereof they are glad, will give them a constantly accelerating impulse in the eter

nal progress of inquiry, by which the finite will seek to understand the Infinite.

It is your work to give to mind the first impulse towards this noble purpose of its creation; to direct its first essays in this interminable course of inquiry, and to form the habits which are best adapted to secure a rapid progress.

In reference to the divers subjects of study included under the comprehensive term "Natural Philosophy," I incline first to caution you not to attempt too much, and then to do justice to all. Do not separate a single branch of science, and attempt to impart a thorough acquaintance with it. The term of your connection with your pupil does not afford time for this. You have on hand many themes of instruction, in prosecuting which the guidance of a teacher is indispensable. If, in addition to a competent knowledge of these, you succeed in inspiring such an interest in the details of natural science as affords a moral certainty that the subject will be prosecuted voluntarily; and such an acquaintance with its principles as will insure its being pursued intelligently, you may be very well satisfied with your work.

To effect this, it appears to me that three things are especially desirable. First, that from her earliest years you keep your pupil's attention alive to all she sees around her, exciting a spirit of inquiry about common things, and quickening her observation, so that a new thing shall never pass unnoticed. That in replying to her inquiries, you ever lay open the analogies between one thing, or mode of existence or operation, and another, so far as she is capable of comprehending them; so that similar circumstances and influences be

ing recognised in one object after another, she is interested at present, and will be materially assisted when she shall afterwards come to the study of the general laws by which the circumstances of analogy are expressed, and the classifications which are founded upon them. This habit of searching for principles is acquired by a young mind much more readily and pleasurably from the objects of nature presented to the senses, than from any abstract study. Scientific books, even the simplest and most elementary, rarely possess sufficient interest to sustain the effort of half-disciplined attention. The exercise of the senses in looking "abroad upon the varied field of nature," under the enlivening influence of fresh air and sunshine, is easy, healthful, and pleasurable. Here is ample scope for the development of that germ of all intellectual activity-a child's curiosity; and for the gratification of curiosity by experiment, which is nature's first effort for the expansion of intellectual powers.

Secondly, That the three great powers ever in operation in the universe, and to one or other of which may be traced all the effects observed in the outward condition of things-mechanics, chemistry, and physiology-should be regarded as the matter to be elucidated rather than any special subjects of their operation. I do not mean that you should lead your pupils to a broad generalization of facts under the influence of these three agencies, this would not be judicious; but that you should bear their operation constantly in mind yourself, and avail yourself of it for her present and future benefit. For instance, during the term of instruction your pupil might possibly become a good practical botanist; but if she do, the time necessarily de

voted to this pursuit will have prevented her from giving much attention to any other department of natural science, and the knowledge she has acquired of botany will not very materially facilitate the prosecution of further studies. But if, instead of this, she have acquired some acquaintance with the leading principles of physiology, and observed their exemplification in the beautiful and varied development of animal and vegetable life, she has gained a solid foundation on which to base additional matter, a key to other stores of trea

sure.

Thirdly, I would recommend the studied avoidance of all the perplexities of verbal peculiarity, minute classification, and cumbrous nomenclature, until such an acquaintance with facts and general principles has been acquired, as shall fortify your pupil from the labour of learning them. It is not the technicalities of science which fix attention, stimulate thought, and captivate taste; and when these are first presented, it is neither unnatural nor blamable that the mind should turn away in disgust, and that all its inquiries into natural appearances should be checked by the idea (a reasonable deduction from experience), that these things cannot be understood without much hard, dry study; and that, pleasant though it may be to possess it, the knowledge is so far off, and the road so extremely toilsome, that ignorance is the preferable alternative. Beware, then, of overtaxing your pupil's willing effort by the imposition of unnecessary burdens. If books of technicalities must be used, it is incumbent on the teacher to have her mind well stored with facts, and enriched with the results of her own observation on the effects of causes and the causes of effects, on all that is pecu