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only of one emotion. These emotions and indications may succeed each other with wonderful rapidity, and hence we may fancy them really blended and co-existing. The countenance of Coriolanus changed during the supplication of his mother and his wife, from an assumed cold dignity, to that state in which, overpowered by natural affection, “ his eyes did sweat compassion.” He did not feel at the same instant as a son, and as the enemy of Rome and the avenger of his own wrongs.
This question is similar to that in which it is inquired whether the mind can, at the same instant, dwell on two ideas?
An Essay on the Art of conveying secret and swift Intelligence, By Richard Lovell Edgworth, Esq. F.R.S. & M. R.I. A.
This essay commences with a learned and elaborate account of the Telegraph :--but, before the author requests our attention to the scientific part of his plan, he produces much pleasant matter. He observes :
• But a still more compendious method of communication was supposed to exist in the 16th century. Is was reported that two magnetic dials, with the four-and-twenty letters inscribed on their cir. cumference, would by means of self-moving hands point to the letters which the correspondents meant to indicate. The great Bacon believed in those sympathetic dials, and the learned Sir Thomas Browne, in his Enquiry concerning Vulgar Errors, gravely informs us that he procured two dial plates, according to directions, magnetised the needles, and repeated the experiment in form, but to his infinite disappointment, “ the needles, though but a span removed from each other, stood like the pillars of Hercules:” he then proceeds to confute the theory “ of this excellent and (if the effect would but fol. low) “ divine conceit,” by shewing that magnetic needles should influence the motions of each other, not in the same, but in contrary directions; had this been the only difficulty, it had been easily obviated by reversing the order of the letters in one of the alphabets.
• Doctor Johnson, in his life of Browne, laughs at him for having taken the pains to try “such a hopeless experiment,” remarking " that he might have satisfied himself by a method less operose, by thrusting two needles through a cork and setting them afloat in two basons of water;" but Browne, he observes, “ appears indeed to have been ready to pay labour for truth.”
• The story of these dials had, I believe, some foundation, but, as it usually happens in popular stories, much fiction has been mingled with some truth.
• If two clocks were furnished with hands, and with dial.plates containing the alphabet, the motion of each of them might be unlocked at a momentary flash or sound, and they might be stopped together at any letter by a second explosion. I'am informed that a very ingenious member of this Academy has spoken of such a con
trivance. With proper precautions, and by substituting numbers corresponding with a vocabulary instead of an alphabet, this invention may be perfected. I cannot help remarking, that by the experiment of Sir T. Browne with two distinct dials, &c. a hint might have been obtained of a practicable contrivance; but by Doctor Johnson's cork, with two needles thrust through it, nothing could be obtained but disappointment. Vulgar tradition and poetic allegory are neither to be implicitly trusted nor hastily despised. The
incredulity of mankind in some instances appears as surprising as · their credulity in others. The disposition to ridicule every scientific
project as absurd until it has been absolutely brought to perfection has been the common topic of complaint among men of inventive genius ; and it is curious to observe that poets, who suffer so much themselves by the taunts of men of the world, and by the apathy of the vulgar, should in their turn revenge themselves upon men of science, and treat their speculations with disdain. Ben Jonson has attempted this in one of his masques with a degree of humour which is not always the portion of those who throw ridicule on science. Merefool, the clown of the piece, consults an adept, who promises to instruct him in all occult secrets, and to shew him apparitions of all the learned men of the ancients; but every man who is called for happens to be busy, from Pythagoras “ who has rashly run himself upon an employment of keeping asses from a field of beans," to Archimedes, who is meditating the invention of
“ A rare mouse trap with owls wings,
And a cat's foot to catch the mice alone.” • Not only the same taste for ridicule, but the same ideas we find repeated, with a slight alteration, at different æras ; Aristophanes and Lucian among the ancients, and Butler, Swift, and Voltaire, the three great modern masters of ridicule, have in various shapes the same ideas, and are alike disposed to confound the ingenious and the extravagant. The best way of parrying the stroke of ridicule is to receive it with good humour ; laugh with those who laugh, and persevere with those who labour, should be the motto of men who possess the powers of invention.
• The late Doctor Johnson, who in his Rasselas ridiculed the idea of the art of flying, lived long enough to see the ascent of the first air balloon.'
Mr. E. accounts telegraphically for the answer given by the Delphic Oracle to Croesus. The story is as follows:
• Cræsus, after having been duped by various oracles, began to suspect their infallibility, and to observe that they made bad verses ; he resolved to try their powers of divination before he put himself to any farther expence in costly offerings. At a certain hour, on a par. ticular day and at an appointed moment, the messengers whom he had dispatched to the different oracles demanded from them “What was at that instant the employment of Cræsus ?”
• All thc oracles were muté, except the Delphic, which immedia mely answered the messengers of Croesus in these inspired lines.
" I know « I know the space of sea--the number of the sand,
I hear the silent-mute I understand.
From brazen pot closed with brazen cover.” • This was precisely the strange employment which the king had privately devised for himself. The answer of the oracle astounded and convinced Cræsus, and seems to have had as powerful an effect upon Sir Thomas Browne, who, in his “ Enquiry concerning Vulgar Errors,” calls this the plainest of all oracles, and deems it the clear. est proof of their supernatural agency. Neither probability nor coincidence could have produced this marvellous reply; it has therefore excited alike the astonishment of the learned and of the ignorant. But the wonder ceases, and an easy solution of the difficulty presents itself, if we suppose that the priests of the oracle were Telegraphers.'
The contrivance of Mr. Edgeworth appears to us both simple and ingenious. Drawings enable us to judge so much better of the form, construction, &c. of a machine, than all descriptions merely verbal, that we shall not attempt any which would probably be unsatisfactory. The part most difficult of comprehension in the memoir is that concerning the Vocabulary: but we feel little inclined to make small objections against an essay, in the perusal of which we have had frequent opportu. nities of admiring the author's ingenuity and learning.
On the Method of determining the Longitude by Observations of the Meridian Passages of the Moon and a Star, made at two Places. By the Rev. Dr. James Archibald Hamilton, Professor of Astronomy at Armagh.
This method of determining the longitude is well known to astronomers. The several corrections, which are required to give sufficient accuracy to it, are here explained fully, and with a considerable degree of perspicuity.
On the Method of taking Radicals out of Equations. By D. Mooney, A. B. Trin. Coll. Dublin.
The object of this memoir is to shew that the rule concerning the method of taking radicals out of an equation, by multiplication, obtains generally; and that, by simple involution, quadratic surds may be taken out of an equation, let the number of terms be what they may.
The author takes an example, vät vor vi + vă+ F and shews that, by involution, the equation may be rendered rational. C 3
The method employed in the former example likewise renders rational x + Vă+vo-vi-vd-VF = 0 care being taken to place it in such a form that, after multiplication, there results the least number of surd rectangles; thus * + vã + vb.= Vīt vd + vf, when multiplied into itself, gives a less number of surd rectangles than when in this form *+ vã vit vd + vi-VT.
Supplement to Mr. Edgeworth's Essay on the Telegraph.
A Description of an Air-Pump of a new Confiruction, &c. &c. By the Rev. James Little, of Lacken, in the County of Mayo.
In this paper is contained a long description of an air-pump, constructed on principles similar to those of Mr. Smeaton and Mr. Cuthbertson. It would require plates, and a much larger portion of our work than we can possibly allot, to give a satisfactory abstract of the contents of this memoir.
On the Application of a converging Series to the Construction of Logarithms. By William Allman, A. B. Trin. Coll. Dublin. The logarithm of the ratio of one number to another is ex
2pd 2pd3 2pdi pressed by the series + +
and where d
354 expresses the difference and s the sum of the numbers, and p the modulus of the system. Now, in the practical application of series, it is desirable, for the sake of conveniency and dispatch, that the series should converge as quickly as possible ; the object, therefore, of the operations in this memoir, is to make the series above mentioned converge quickly. The author thus explains his method of producing a quickness of conyergency:
It is evident, that the less d is in respect of s, the faster the series will converge ; so that the construction of the logarithms of prime numbers, will be rendered more easy and expeditious, by finding two great products, which shall have a small difference; one of which products shall be composed entirely of factors whose logarithms are already known, and the other shall have in its composition, the number whose logarithın is sought, or some power of that number; and, if it have any other factors, the logarithms of these factors must be previously known.
"Having found such products, we may, by the application of the above-mentioned series, find the logarithm of their ratio to each other ; which is the same with the logarithm of the ratio of the first product (or that which is composed entirely of factors whose loga. rithms are known) divided by the factor or compound of factors whose logarithms are known (if there be any such ) in the latter produçt, to the prime number whose logarithm is sought, or some power of that number. Then, from the logarithm of the antecedent,
and the logarithm of the ratio, we have, by addition of subtraction, the logarithm of the consequent.'
POLITE LITERATURE. Soine Hints concerning the State of Science at the Revival of Letters, grounded on a Passage of Dante in his Inferno, Canto iv. v. 1.30. By the Right Hon. the Earl of Charlemont, President of, the Royal Irish Academy, and F.R.S.
In the poem of Dante, written about the year 1300, the poet describes the Elysium prepared for Pagan worthies, and gives' to. Aristotle the first place among the antient philosophers, in the following passage :
• Poiche'nnalsai un poco piu la ciglia,
Vidi 'l Maestro di color che sanno
Seder tra Filosofica Famiglia
Quivi vidio e Socrate, e Platone,
Che ’nnansi agli altri pui presso gli stanno. • My eyes a little raising, I descried
The sov'reign master of all those who know,
Sitting among the philosophic race,
There I beheld both Socrates and Plato,
Who prior to the rest stand close beside him. This passage being a testimony of the reverence in which Aristotle was held in the darker ages, at the first revival of letters, the noble Earl proceeds to assign the causes of this reverence ; and to point out the circumstances which gave mankind a disposition and an ardoor for the subtle, refined, and disputatious philosophy of the Stagyrite.
The ingenious remarks and displayed learning of the noble author claim attention and praise ; yet we must observe that the parts of the present memoir are not sufficiently connected, and that its object is not sufficiently determinate. The title of the paper, however, may be said to have prepared an ex. cuse against any objection of this nature.
Reflections of the Cheice of Subjects for Tragedy among the Greek Writers. By William Preston, Esq. M. Ř. Í. A.
The subjects of the Grecian tragedies are tales of horror ; Orestes, pursued by the Furies; the horrid Feast of Atreus; Oedipus, incestuous, blind, and mangled; Hercules tortured by his envenomed robe ; Medea, the murderess of her own children, &c. Such were the favourite themes of the Grecian Muse. The inquiry in the present essay is concerning the causes which led the Greek tragic writers to seek so sedulously, a history, for subjects of such aggravated horror; and accord