that wants length (says he) is impeded by its continual ascent and descent; moreover, the tendency of the action of the upper sails of a ship is not only to propel horizontally, but to elevate the stern and to depress the head; which elevation and depression must be more resisted, as the distance between the insertion of the mast and of the head and stern is greater, cæteris paribus. 3dly, The vessels are too narrow.

The remedy proposed for these defects is (as may be easily inferred) to give to the ships great horizontal expansion; and for this end the construction of their hulls must be changed. The bows and sides are to be constructed very differently, as the end to be answered by them is very different; the one is to present as few points of resistance as possible, the other as many; the one is to facilitate the ship's passage, the other is to prevent her disposition to make lee-way: but, according to the present method of construction, a very small part of the ship's side is perpendicular to the horizontal pressure.

The author next controverts an argument of seamen and ship-builders, in favour of the depth of ships, founded on what is technically called "a gripe of the water below the power of the surge."

The alterations proposed by Sir George Shee are, in a few words, increase of horizontal dimensions, and a change in the form of the bows and sides. In regard to the form of the latter, they should resemble a large lee-board, used in Dutch vessels to prevent a disposition to lee-way.

Sir G. S. blames the construction of the vessels employed in carrying the mails from Dublin to Holyhead. Although they are expressly built for speed and accommodation, yet they require an absolute loading of ballast to prevent them from oversetting; and their draft of water is such that, although small vessels, they can only float on the Dublin Bar at a particular time of tide. From their want of length, and from their excessive depth, they sail so slowly, that a ship called the Favourite, a light, long vessel, fitted out by private individuals, has made her passage to Holyhead in nine hours; when the two packets, which weighed anchor at the same time, occupied twelve hours in performing theirs.

These suggestions of the ingenious Baronet are, we think, deserving of notice; for to England the perfection of naval architecture is of great moment :-but mere theory can perhaps effect little. The antients, who made very considerable progress in the art of constructing ships, seem to have relied entirely on observation and experiment.

Memoir on the Climate of Ireland. By the Rev. William Hamilton, M. R.I. A.

The object of this memoir is to prove that the winds, and particularly the westerly gales, have of late years blown over Ireland with a violence unknown to former times. The author appeals to what he calls the natural regifters of the effects of the winds; viz. the trees of the country, the sands on the sea-coast, and the tides. It is well known that, formerly, pines, and particularly that species called the Scotch fir, grew on the northern and western coasts. Vast roots and trunks remain in places in which a twig even of the most hardy kind can now with difficulty be reared. In the counties of Westmeath and Antrim, Donegal, and on the coasts of Enishowen and Rosses, pines formerly arrived at the age of 120 years, and were more than a yard in diameter, and 50 feet in height. In regard to the sands, these have in many places overwhelmed houses and towns; witness, the ruins at the entrance of the river Bannow in the barony of Forth, in the county of Wexford; and the decaying state of the mansion-house of one of the noble families of Hamilton, situated in the peninsula of Rossgull, between the harbours of Sheephaven and Mulroy, in the county of Donegal. -The increase of the tides is well known to those who have had occasion to construct or to repair embankments.-A compensation for the evils arising from the prevalence and fury of the westerly winds is a more even temperature than Ireland formerly experienced; for the western winds blow over the waters of the Atlantic, which are less sensibly affected by the variations of cold and heat than land would be. From a balance of loss and gain, the author concludes that Ireland is ameliorated since the westerly winds have prevailed. In his own language:

To sum up matters, then, with truth and brevity-A density of population, surpassing that of the vaunted millions of undepopulated France; a copious export trade in provisions of various kinds, unequalled by any kingdom whose inhabitants are proportionably numerous; and a staple manufacture unrivalled in general use, in certainty of produce, and intrinsic value; are circumstances which have not fallen to the lot of other nations, and bring with them clear and irrefragable evidence to demonstrate a salubrious country, a genial climate, and a fertile soil in Ireland.'

The author conjectures that, as the westerly winds have raged since the destruction of forests in the time of James I. these forests broke and mitigated the fury of the tempests; especially as the limits of stormy currents may be within 100 yards of the surface, since the lower mass of air often pursues a different course from the upper.

REV. MAY, 1799.

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Essay

Essay on the best Means of ascertaining the Areas of Countries of considerable Extent. By the Rev. James Whitelaw, M. R.I.A. Having shewn that the common projections (stereographic, conical, and circular) are unfit for mensuration, this gentleman proposes a method of determining, to a considerable degree of accuracy, the areas of maps on the conical and circular projections. The method proposed is briefly this: Draw the contour of the country, and observe what quadrilateral spaces lie within it. The quadrilateral spaces form what is called the integral area, and that without it the fractional. The integral area is easily and accurately found, for the area of a zone included between two parallels is had by multiplying its sine in miles and decimals of a mile by 21600 (circumference of a great circle in such miles): divide this product by 360, and we have the value of a quadrilateral space. The fractional area is next computed, but by a method which we cannot well explain here.

Three Schemes for conveying Intelligence to great Distances, by Signals. By John Cooke, Esq. M. R. I. A.

We do not see any thing particularly worthy of notice in these schemes; they may be multiplied ad infinitum.

Observations on the Power of Painting to express mixed Passions. By the Rev. Michael Kearney, D. D. M. R. I. A.

This is a criticism on a remark of Sir Joshua Reynolds, concerning the impracticability of describing the expression of mixed passions. The memoir is short, and the criticism is given with considerable ingenuity and much modesty; yet, in our opinion, it will not overthrow the decision of the late President of the Royal Academy.

In the countenance, doubtless, may be discovered either permanent qualities or sudden emotions; sweetness of temper, strength of intellect, joy, despair, &c. The dignified form, the character of martial gallantry, and the marks of an amorous temperament, observable in the statue of Paris by Euphranor, might justify the assertion that in it could be discerned the judex Dearum, amator Helene, and interfector Achillis, whatever indication of inward emotion the countenance is capable of assuming, the pencil of the painter may imitate :-but can it express the contest of different emotions? Can the soul be agitated by two different passions at the same instant? If not, the countenance can exhibit, in one instant, the indication

* Quadrilateral spaces are formed by the parts of two parallels of latitude distant from each other one degree, and of two meridians distant one degree of longitude.

only

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 circumference, 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 follow) "divine conceit," by shewing that magnetic needles should in-. fluence the motions of each other, not in the same, but in contrary directions; had this been the only difficulty, it had been easily ob viated 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

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trivance.

trivance. With proper precautions, and by substituting numbers corresponding with a vocabulary instead of an alphabet, this inven tion 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 Croesus?"

All the oracles were mute, except the Delphic, which immedi ately answered the messengers of Croesus in these inspired lines. "I know