Introduction to his Principles of Natural Philosophy, declines giving an opinion of what the essential nature of the power is, called gravitation. The object of the former was, to point out the means by which the natural mind progressively acquires the knowledge it may possess, and the boundary of it, in its observations of the natural laws which regulate the material world :—the object of the latter was, to point out the effects of the power called gravitation, as governing by an immutable law the visible creation;-that it is not an essential property of material substances, but an invisible power which regulates their motions.

Hence, natural knowledge solely consists in the perception of the laws which regulate the visible material world, and which we call the laws of nature; and it is from our right or wrong perception of those laws, our correct or erroneous inferences ensue; and consequently, on that perception of the mind depends correct or erroneous opinions.

For example:-The perception of certain

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actions of mankind, when influenced by the passions, destroying the peace and harmony of society, in committing murders, thefts, &c. has called forth human laws to restrain them. Which laws are founded on the natural law: that the punishment they inflict, will prevent such actions, from the general fear of pain perceived in our nature. Again, the same natural law regulates our assent in commerce. perceive that the price of a commodity is regulated in proportion to the demand and supply; which law is perceived to be constant, and has ever existed in society, although it may have escaped the general perception of mankind: that is, such effects are constantly produced in the affairs of mankind, by such immutable law, which some perceive, and others do not, by their attention being more or less directed towards the subject. And, the same perception of the natural law is applicable to every department of human knowledge. In chemistry, physic, anatomy,* astronomy, mechanics, &c. and the correct perception of

* We are speaking of mental knowledge, not of skill.

those laws in each department, constitutes good chemists, good physicians, good anatomists, good astronomers, good mechanicians, &c. :-as the wrong perception of those laws, constitutes bad ones, in each of those respective departments. For instance, Sir Isaac Newton was a good astronomer, because he perceived the true law, which regulates in space the motions of the planets; and demonstrated the truth of those motions, by their being governed by strict mathematical laws, and by an invişible power, called gravitation; and which he perceived equally ruled in every part of space, within the reach of telescopic observation, as upon this earth. But, we cannot say that Descartes was a good astronomer; because he reasoned from fancy, and not from facts, perceived in the immutable laws of the creation. We may, however, now say, there are better astronomers in the present age, than Sir Isaac Newton was; not as discoverers of more important laws, but by their possessing the knowledge of the laws which he perceived, together with the subsequent discoveries to the present time. So in chemistry, those who perceive the greatest

number of the physical laws which govern the material world, and can prove by experi ments more laws hitherto undiscovered, are the best chemists.

Our faculties are, therefore, employed, whether in these departments, or in the cultivation of the earth to obtain the food and comforts of life, by acquiring a knowledge of the physical laws which govern this material world. And from invisible causes we reason by their effects, as in gravitation, electricity, &c.—that is, the changes produced in the visible creation, are effects of powers invisible. So in man:-from the effects or actions produced by the malignant passions, or otherwise, we discern whether he be a good man, or a bad one. When he is most influenced by those passions, in committing murder, thefts, lying, &c. he is commonly called a bad, or diabolical character; which the criminal laws are intended to restrain. But when his actions are generally governed by right reason, in benevolence, justice, and truth, he is called a good man,-and for such persons no criminal law is required.

Our knowledge being, therefore, limited to the perception of the natural laws that regulate the material world for our guide it is clear we can obtain no knowledge of what the nature of the mind is, which perceives those laws, nor from whence it emanates. Neither can we know what those malignant passions are, called envy, malice, hatred, jealousy, which cause misery among us, and so far assimilate us with the brute creation, by their being generally perceived in brutes." At the same time, we do not perceive the mind of reflection in brutes: and Mr. Locke has shown it is that power which places man above them in the order of creation. And the Scriptures also inform us that it is the mind, totally uninfluenced by such passions, which gives dominion over them. And which is evident:-for, if the mind of reflection be taken from man-what is he more than the brute? But, instead of the reflecting mind, the malignant passions be taken from him-what is he less than the reasonable man?

But, we have also evidence of the passions