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in the creation around, we are forced upon the conviction that the Almighty acts in this respect with that economy of creative energy, which, although infinitely more perfect in its degree, has, nevertheless, its visible type in that husbandry of our resources, that disposition to economy in our efforts, which impels us always to avail ourselves of the simplest possible means of effecting all that we wish to do.

Thus, when, in reasoning upon any hypothesis, we are forced back upon final causes, it is sound philosophy to judge of the probability of that hypothesis according to the simplicity or complication of the final causes to which we are thus compelled ultimately to refer it. If, for instance, there be two hypotheses, by one of which we shall be compelled to fall back upon a double operation of the hand of the Almighty, whereas the other resolves itself into a single effort of his will, then is the latter hypothesis, according to the analogy of nature, more probable than the former, and that INFINITELY.

Now, as has been before explained, a motion of rotation having been communicated to the earth, it must also, in consequence of the force applied to communicate this motion, have had further a motion of translation, unless another, or second force, had been communicated to it in a direction through its centre, precisely equal to the first force, and parallel to it, but in an opposite direction; thus having as it has a motion of rotation, if in other respects it be at rest, the earth must, in the beginning, have had two distinct impulses communicated to it from without, in opposite and parallel directions, and at different, but not opposite points of its surface*.

Again, this hypothesis of the quiescence of the earth in space, involves necessarily the revolution of the sun about it; a third impulse, therefore, must be supposed to have communicated this motion to the sun. Reasoning, then, upon the hypothesis of the sun's annual revolution, we are obliged to fall back upon three final causes, three distinct operations of the Deity, whereas the opposite hypothesis of the annual revolution of the earth subjects the whole of the phenomena to one. One will, one impulse, one developement of the powers of Him who spake and it was done.

This argument (and indeed every one of those which have yet been set before the reader) is perhaps in itself conclusive. Different arguments in proof of the revolution of the earth, have been adduced rather because it may be considered necessary to a knowledge of astronomy, that the reader should be put in possession of all that has been said on the subject, than because it is thought that the arguments are in any way necessary to support one another. The accumulation of proofs, any one of which is sufficient, does not perhaps in reality consti

It has been calculated by Bernouilli, that the single impulse by which the earth was made to revolve upon its axis in the time which we know it to revolve, and at the same time to move forward in space as we know it to move, must have been communicated to it in a direction perpendicular to the line drawn from it to the sun, at a distance further from the sun

than the earth's centre is, by about the s part of the earth's radius, or at a distance about 25 miles further from the sun than the centre of the earth is. Similarly the impulse communicated to Mars must have been at a distance of of its radius from its centre-that of Jupiter of 13, and that of the moon at ro.

tute any accumulation of evidence; on the contrary, it is perhaps more according to experience, to assert that everything in the shape of proof which is added to that which is already proved, tends to weaken its authority. The evidence on this point is, however, too strong to be shaken by any method of arguing upon it, however illogical; yet another proof of the annual revolution of the earth will therefore now be added.

Whatever may be the true explanation of the phenomena of light, certain it is, that their origin and mode of operation is subject to the usual and known laws of mechanical action. The perception of light is the effect on impulse, somehow or another taking effect on the nerves which belong to the retina of the eye. Now this being the case, it is manifest that the effect of that impulse may be modified by the circumstances under which the eye is placed. If, for instance, the eye be at rest, the effect of the impulse on the eye and the resulting perception of light, will be in the same direction as that in which the impulse is made. If it be in motion, and the velocity of its motion bear any finite relation to the velocity of the impulse of the light, then the effect on the eye, and the consequent perception of light, will not be in the direction of the impulse of the light, but in a direction compounded of the direction of the eye's motion, and the direction of the impulse of the light.

Thus, if a person standing at rest be struck by a ball obliquely from above, he will feel the blow in the direction in which the ball moves; but if he be in motion, the direction in which he feels the blow will be compounded of that of the ball, and that of his own motion.

We may thus ascertain what that compounded direction will be. Let us suppose a motion equal to that of the man to be communicated both to him and to the ball, at the same instant of time, but both in a direction precisely opposite to the man's actual motion-the same motion being communicated to both man and ball, the effect of the ball upon the man will not be altered by this motion thus added to it. But the man, having now impressed upon him a motion, equal and opposite to that with which he is already moving, will thus be brought to rest, and the ball will have two motions communicated to it, in virtue of which it will move in the direction of the diagonal of the parallelogram whose adjacent sides represent these motions; thus, then, its effect upon the man now brought to rest will be in the direction of that diagonal; also, by the hypothesis by which we have brought him to rest we have not altered the effect of the ball upon him; restoring, therefore, the circumstances of our first hypothesis, the effect of the ball upon the man in motion, will be in the direction of the diagonal of the parallelogram, one of whose sides represents the motion of the ball, and the other the motion of the man.

If the direction of his motion be towards that from which the ball comes, the effect will therefore be in a direction still more inclined downwards than the actual direction of motion of the ball, and if it be from that direction it will be more inclined upwards. Thus let him be moving in the direction ac, so as to describe AC in one second of time, and let the ball describe BA in one second of time. Then communicating to the ball and to the man the motion CA, equal and opposite to AC, the man will be brought to rest, and the ball will have the two motions ca

It is

and BA communicated to it, and will move in the direction DA. therefore in this direction, which is lower than its proper direction,

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that it actually takes effect. Similarly, if it had come from behind in the direction EA, it would have produced its effect, when combined with the motion of the man, in the direction FA, which is higher than its proper direction. Now for the impulse of the ball, let us substitute that of a wave of light, and let us suppose the spectator to be borne along with a velocity which has a certain finite proportion to that of the propagation of such a wave of light. The effect of the motion of the spectator on the direction in which the impulse of the light is perceived, will be precisely like that of the ball. If he is borne towards the object which is the origin of the wave, the direction in which the impulse is perceived will be lower, and if from it, higher than that in which it actually comes, and thus the objects towards which he is moving will appear lower to him, and those from which he is moving higher than they really are. If, then, the earth move in its orbit, and if the velocity of its motion bear any finite proportion to the velocity with which the light of the fixed stars is propagated to an observer on the earth's surface, then those towards which the earth is moving in her orbit will always appear to him lower than they really are, and those from which she is moving higher. And if she is not moving with any such velocity, then the light of the stars will appear to come to him in the direction in which it actually does come, and the stars will not appear higher when the earth's motion carries him from them, than when it carries him towards them. Now light travels at the rate

of 192,000 miles per second, and the earth at about 19 miles per second. Thus, although the velocity of the earth bears but a small proportion to that of light, yet it does bear a certain finite and appreciable proportion. There will then be a finite and appreciable, though scarcely apparent depression, of those fixed stars towards which the earth is moving, and elevation of those in the opposite regions, provided the earth moves in its orbit as we assert; and if it do not, there will be no such depression or elevation. Now this difference of the true from the apparent position of the stars does exist; it was discovered by Dr. Bradley, and is called the aberration of light.

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MISCELLANIES.

French Account of the Statistics of the
Book-trade in Germany and England.
GERMANY still stands pre-eminent in

France, the former number giving 13, the latter 4 sheets for each individual. In England, including pamphlets, reprints, newspapers, magazines, &c., the value of printed works in 1833 amounted to £2,420,900. sterling.

the extent of its Book-trade. The annual value sold is estimated at £860,000. sterling; thirty years ago the trade was This trade is almost entirely in the in the hands of only three hundred hands of the London booksellers, of booksellers, or publishers. At present whom there are 832, nearly as many as there are not less than 1094, including there are in Germany. The division of ninety-two commercial houses of Swit- trade in this central mart of bookzerland, Hungary, Prussia, and its trading is remarkable; there are bookPolish provinces. Through the Ger- sellers who entirely devote themselves manic Confederation there is one book- to the sale of religious works, others to shop to 93,000 souls, while in Austria that of elementary works for instruction, there is only one to 122,222. The pro- and so on. Exclusive of pamphlets, gression, as regards intelligence, is still reprints, and newspapers, the number more striking in Prussia, where there is of volumes published in England rose a book-shop to every 33,899 persons; in from 1105 in 1828, to 1507 in 1833, 1830, there were 200, which, in 1833, between which periods there was an had increased to 293. At least fifty-annual increase of about ninety-two or eight new book-shops have been esta- ninety-three volumes, caused blished in different parts of Germany between Easter, 1832, and Easter, 1833. The number of works published in that country has increased in the following proportion: (1827) 5000, (1828) 5,600, 1832, in which year many pamphlets were published) 6,122, (1833) 4,635 (?). Of these, Austria furnished 290, Prussia 1058, Saxony 1810. Leipsic is the centre of this immense commerce.

If we compare the total number of works published in Germany from 1814 to 1820, which were 50,393, and the number published in France during the same period, which was only 16,528, it would not at first be imagined that the proportional increase of literary works has been much greater in the latter than in the former country, but so it is; the aggregate amount of works was barely doubled in Germany, while in France in 1826, the number published was 4347, or four times as great as in 1814. In 1828, the French publications were 7616, a number never reached in the catalogue of the celebrated annual Leipsic fair. The fluctuations in the labours of the French press are to be attributed to political events. In 1811, forty five millions, and in 1826, 144 millions of sheets were printed in

rapid progress of "cheap literature," by the which has effected a reduction in the mean price per work from 12s. to 10s.7d.

New Surveying Instruments.

M. LALANNE, Engineer of the Ponts et Chaussées, in France, has laid before the Académie des Sciences three instruments for topographical surveying, which, if they accomplish all that the inventor promises, correctly and with facility, will be eagerly sought after. To the immense number of surveyors, who are about to commence operations in every part of the United Kingdom, under the numerous Railroad Acts which have passed this session, such instruments would be invaluable. They are, 1st, a Levelling Instrument, or Carriage, which it is only necessary to run over the ground, the levels of which are desired, and the section is at once obtained; 2nd, a Drawing Instrument, which lays down the plan of the ground; and can be mounted on the carriage of the Levelling Instrument; 3rd, a Power-measuring Instrument, or Dynamometer, which exhibits the effort exerted on every point of the line passed

over.

Mode of ascertaining Proportion of

Carbon in Cast-Iron.

BERZELIUS, in a letter communicated by M. Pelouze, to the Société Philomathique of Paris, announces that he has discovered a very short process of analyzing the various kinds of Cast-iron, and of ascertaining the exact proportions of carbon that they contain.

quiries into the Polarization of Heat. The result, at the first view, appears very complicated, but they cease to be so on the admission, that the calorific flux from terrestrial sources is composed of rays, which, like those of solar heat, have the property of being more or less transmissible by certain solid and liquid media.

New Botanical Society.

His mode consists of boiling the iron in a bichlorate of copper, slightly aciduSEVERAL meetings have recently taken lated with hydrochloric acid; then to boil the residue with carbonate of soda. place, with the intention of forming a The weight of this second residue, society, to be entitled, The Botanical washed and dried, gives that of the Society of London. The attendances, carbon. This process has been repeated tions and donations to a library and and promises of support by subscripby M. Gaultier de Claubry, who found that, to succeed, it was necessary the herbarium have been numerous and chlorate should be strongly acidulated satisfactory. A committee is now rebefore adding the iron in filings, other considering the laws, regulations, &c. wise copper is precipitated; but with The formation of the society is said to this precaution, the analysis may be be patronized by Professor Lindley, and completely accomplished in ten or twelve minutes.

Temperature of Space.

other eminent botanists.

Consumption of Oxygen by burning
Wood.

THE result of some reflection upon the MM. PETERSEN and SCHÖDLER have degree of cold, registered by Captain Back, when in the Polar regions, in-applied themselves to a long and most duced M. Arago to state to the Aca-fatiguing series of experiments in order démie des Sciences, that it was his opinion the temperature of celestial space could not be lower than the maximum of cold mentioned by Captain B., viz. 102° Fahr. below the freezing-point. M. Poinsot, on the contrary, thought such a consequence ought not to be drawn from the data, and contended that the temperature of the upper strata of the atmosphere must necessarily be lower than that of space.

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which is taken from atmospheric air to determine the quantity of oxygen in effecting the perfect combustion of a given weight of several kinds of wood. determinations made by them, of the quantity of oxygen which each kind of wood contains before combustion, and of the quantity of additional oxygen necessary to burn it completely.

This result has been deduced from

These experimenters arrived at the first of these necessary data in the following way:-Each specimen, carefully reduced to powder, was exposed in a drying apparatus, and there heated and exposed to a current of dry air until no further loss of weight occurred. It was then weighed with every precaution, and mixed with oxide of copper in a hot porcelain vessel, The mixture, after having been deprived of all hygrometric moisture in a vacuum, was burnt in a proper tube. From the water and the carbonic acid which were obtained, were deducted the carbon and the hydrogen, and the amount of oxygen contained in the wood ascertained.

Twenty-four kinds of wood were examined in these experiments. The specimens were taken, in all cases, from

the trunk of the tree.

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