THE SUN SHINES.

"Shines" is the "verb,' ," "what is said;" "sun" is " subject," the thing of which we speak.'-Russell, p. 41.

It was not until after a very patient consideration of this sentence, that we, at length, discovered its construction and meaning. At first, we did not know whether to think the learned author had been guilty of a cockneyism, Shines is the verb what is said, &c.' or, had discovered that the pecuJiar use of the word what (which by the way he calls a conjunction) was according to the strict usage of our language. But, afterwards, on recollecting his definition of a verb, we satisfied ourselves that he thus intended to describe the verbal power of the word 'shines,'-another proof, if any were wanted, of the consequence of bad definitions. In page 43, several sentences are rendered obscure, and indeed ungrammatical, by the omission of the article. We shall quote one of them, and, at the same time, enter our protest against the mode of parsing the sentence.

'A WINDOW SHALT THOU MAKE in the ark.'-Gen. vi. 16.

"Window" is object set before the verb make, and "shalt" is verb set before the subject "thou."'—p. 43.

In copying this extract, we have taken the liberty of discarding various inverted commas, which so superabound throughout Dr. Russell's publication, that we know not whether they most disfigure his pages, or obscure his meaning. We are confident that both these, and the Arabic figures used as representatives of words, will greatly impede its circulation.

We have one objection more to bring against the labours of Mr. Murray and Mr. Lennie. They systematically illustrate the rules of orthography, etymology, syntax, and prosody, by exercises in bad English, which they expect their pupils to pore over and correct for the purpose of imbuing their minds with a pure taste, and of moulding their ideas into good English. We have read of a father adopting a similiar practice, in order to correct the vices of his son; but if the experiment is held doubtful in morals, it is not less so in language. We do not believe that a system so vicious can long maintain its ground. When men go to bad speakers to study pronunciation; when they resort to the dialects of Lancashire and Somersetshire for specimens of the best spoken English; then will we consent to see our youth instructed in the beauties of language through the medium of false orthography and a rugged phraseology.

Grammar ought to be taught from the purest models. Passages from authors, containing defective English, may, properly enough, be quoted to show how the rule is violated; but

such a use of them is essentially distinct from that resorted to by our grammar compilers. The pupil's chief exercise ought to be one that we have never seen recommended, namely, of finding examples from books and making them for himself. He should be encouraged to do this in every stage of his progress, and be continually furnished with a large variety of illustrations, instead of being dragged through that dull routine of stupid labour to which boys are apprenticed when they are set to learn Murray's or Lennie's Grammar.

Having concluded our remarks upon these school-grammars, we shall briefly recapitulate the several grounds of our objections to them. 1st, They make the art of speaking and writing the English language a mere system of rules. 2d, The system on which they teach it is not inductive. 3d, Their definitions are miserably defective; and, 4th, The exercises for the pupil's practice, instead of being selected from the well of English undefiled,' are bad specimens of bad English.

We have placed Dr. Russell's Grammar in our list at the head of this article, not because we rank it with the other two in point of merit, but because it is one of the same class. Such books as Lindley Murray's and Mr. Lennie's are totally unfit for the wants of the present age; and we hope to see them very soon superseded by others of a better kind. Dr. Russell's treatise we receive as a valuable contribution to our collection of school-books. Several of its defects may be removed in a future edition; and we should recommend to the former head master of Charter House School, a complete revision of his chapters on the verb. The two auxiliary verbs should be conjugated in all their tenses, and a complete paradigm of the active and passive verbs should also be added, to adapt the grammar for general use and a wide circulation.

GRAVITATION.

Gravitation: An Elementary Explanation of the Principal Perturbations in the Solar System. (Written for the Penny Cyclopædia, and now previously published for the Use of Students in the University of Cambridge.) By G. B. Airy, A.M., late Fellow of Trinity College, and Plumian Professor of Astronomy and Experimental Philosophy in the University of Cambridge. London: C. Knight, 1834. THE work before us is the representative of a class, of which we could wish the number were greater. We consider its appearance as a remarkable epoch in the history of astronomical

instruction, and we shall proceed to give the grounds of our opinion.

If we take any one of the mixed results of experiment and analysis which constitute the greater part of our knowledge of physics, we shall generally find that there are but two ways in which it is known. A very small proportion of readers is aware of the manner in which the experiments were made, and has followed the mathematical deduction of the resulting law. All the rest receive both the method and the result from the authority of the first mentioned class, as if they were facts of history or any other matter resting on positive authority. In this manner the educated world is not ignorant, either of the laws of nature, or the history of Greece; but the sort of knowledge which they acquire of the first is no more by a train of inference than that of the second.

Such, it would appear at first sight, must always be the case, until considerable mathematical learning is a part of all education. And by far the greater number of popular works on physics have been written with no other view than to make known, on the authority of Newton, Laplace, &c., the results of analytical investigation. It is easily credited, on the combined assertion of observers and geometers, that the moon's mean motion receives an acceleration of so many seconds per century, and that this phenomenon is caused by the action of the planets upon the orbit of the earth. But we must observe, in the statement of the preceding phenomenon or of any other, that there are two considerations, either of which may be made the subject of a scientific deduction: first, the sort of phenomenon asserted-the moon's mean motion undergoes a continual alteration, such as may arise from the attraction of the planets, if there be attraction-secondly, the numerical amount of the phenomenon, an acceleration of eleven seconds per century. It does not by any means follow that even the mathematical mode of establishing the first is above general comprehension, because that of the second is so; and it has long been known that many a phenomenon, the quality of which was even ascertainable without any mathematics at all, required great advances in that science before its exact law and quantity could be ascertained.

The Principia of Newton, in establishing, to a certain extent, the mathematical theory of the planets, first created the distinction between a sufficient reason for the sort of result to be expected, and accurate determination of its law and quantity. The eleventh section of that work forestals the third book as to all the inequalities which are geometrically treated in the latter. It is there shown, without mathematical symbols, though the reasoning is generally mathematical in its nature,

-not how much, or according to what law, the moon's nodes will regress; but that they will regress, and why-not how much tide the moon will raise, but that there can be no attraction without a tide, more or less; and so on. But this section (as Cambridge men well know) is more difficult by far than any of the others. The style of Newton is always condensed and obscure the subject was new, and had not received the illustration which transmission through successive minds never fails to afford. And we may add, that though mathematical symbols are avoided, yet mathematical reasonings and results are verbally expressed, and in a shape of such extreme compression, as can only be well conceived by those who have seen the development which Cambridge tutors generally find it necessary to give to the corollaries of the celebrated sixty-sixth proposition, in order to afford their pupils the least chance of understanding them.

On the subject of the eleventh section, Professor Airy says,

'The advanced student who exults in the progress which the modern calculus enables him to make in the Lunar or Planetary Theories, perhaps hardly reflects how much of the power of understanding his conclusions has been derived from Newton's general explanations.'

On this point we must enter a difference of opinion. That the author of the work before us should, in his younger days, have been able to put the eleventh section to the use for which Newton intended it, no way surprises us. We speak from what we know of ourselves and others at Cambridge, and we feel quite sure that the number of those on whom the section in question throws any light, is very small indeed. We found the third book a greater help to understanding the eleventh section, than vice versa, and the greatest cause of exultation which we found in the modern calculus* was in the demonstration we there found, that the inequalities of the lunar system were not so utterly unintelligible as, from the eleventh section, we imagined they might be. It is true that where the student of the modern calculus returns again to Newton's Eleventh Section, he cannot fail to receive new views. But, with all our admiration of that really wonderful part of the Principia, we must say to Professor Airy, in reference to his opinion upon it, "Mutato nomine, de te fabula narratur;" what he has said of Newton, others will have better reason to say of him.

If we trace the history of the eleventh section, we shall find a disposition among the commentators to avoid it altogether,

The supplement On Newton's Lunar Theory, in the fifth book of the Mécanique Céleste, is a striking proof how much a little modern algebra will help the student of Newton,

which will sufficiently show,-not that it needed no comment, for that is an opinion which has never been advanced,—but that the task was above attempting. Let us begin with Maclaurin's explanation of the progression and regression of the moon's nodes. (Book IV. chap. 4. § 10.)

'It is certain that if the earth and moon were always acted on equally by the sun, they would descend equally towards the sun; the plane determined always by these two lines would descend with them, keeping always parallel to itself, so that the moon would appear to us to revolve in the same plane constantly with respect to the earth. But the inequalities in the action of the sun described above will bring the moon out of this plane, to that side of the plane, on which the sun is, in the half of her orbit which is nearest the sun, and towards the other side, in the half of her orbit which is farthest from the sun. From which we have this general rule, &c.'

From the mere statement of a result, or rule, as it is properly called, the detail of the phenomena is entered into, and all further difficulties are resolved by an appeal to what is called "the general principle, in § 10." Maclaurin was perhaps right in not trying to explain what he could not elucidate; and certainly his account of Newton's discoveries is, as far as it goes, a clear book. But this is not grappling with the difficulties of the eleventh section. Pemberton (we speak from recollection) pursues much the same method.

A commentator (who is very little known) named Domckey* (Latinized Domckius) has taken a more direct and difficult course, and does attempt some real detail of Newton's arguments. But except in the adoption of mathematical symbols, he only differs from Newton in using a less condensed mode of expression. Dr. Clarke has skipped the sixty-sixth proposition altogether. Emerson has added a very few verbal explanations of some obscure sentences. The Jesuits have added notes which, except where they are mathematical, are as difficult as the text. Madame du Châtelet has given a literal translation; and Clairaut, in his 'notes to her work, describes rather than explains Newton. In more modern times, though many Cambridge tutors have compiled manuscript explanations of every part of Newton, and though many such manuscripts on other subjects are published, nothing more of the Principia has, to our knowledge, seen the light, beyond the first three sections, published by Mr. Carr. We do not speak of Mr. Whewell's treatise on the subject, in the second edition of his Dynamics, because mathematical aid is professedly introduced. On the continent, much as has been done in popu

* Philos. Math. Newt. illustratæ, tomi duo. Londini, 1730,