« AnteriorContinuar »
Dr. Hutton, having deduced the law of resistances to spherical bodies moving in the air, proceeds in a series of important problems in Tract 37 to apply it to the determination of the most essential particulars in the motion of military projectiles. Here many of the solutions are both elegant and satisfactory. But the grand problem by which the actual trajectory of the projectile may be determined still remains unsolved, and must do until some philosopher possessing an adequate portion of Dr. Hutton's science and zeal, shall be so favourably circumstànced as to carry through another set of experiments with a special regard to that object. We shall terminate our quotations, by transcribing our author's new approximate rule to find the elevation of a gun to hit an object at a given distance.
'Let D denote the given distance of the object in feet; d the diame. ter of the ball in inches, obtained from the table of weights and diameters in problem 10; b the weight of the ball, and c that of the charge of powder, both in pounds; V=1600
2. the projectile velocity, as given in problem 13; T', the last velocity with which the ball strikes the object; and t the time of the ball's flight. Then
D 'Divide D by 1338 d, considering the quotient as a log.
* Take N= the natural number of the log.
log. of (
64 D 2
• Take v=
to q the final velocity : q being = 231, N
, an approximation near enough, Then, 16t2 = is the height above the object to be pointed,
(V + 0) 16 t? 64 D Or
is the tangent of the angle of elevation. D
(V + 0)? “So that, the height of the mark to be pointed at, above the object, is nearly as the square of the distance, and the angle of elevation simply as the distance, the projectile velocity being the same. But, in the case of different velocities, the height and the angle will be reciprocally as the square of the velocity nearly.'
It will be recollected that our author gives the above merely as an approximation. We have been at the pains to apply it to the results of a great many accurate experiments by Dr. Hutton and others; and find that if the angle of elevation obtained by these theorems be diminished by its fifteenth part, it will then agree very nearly with the actual practice of artillery,
The 38th and last tract in this collection contains 34 miscellaneous practical problems, illustrating many of the principles in the preceding part of the work. But of these we dare not, after looking back on what we have written, say more than that the solutions are ingenious and accurate; with the exception of the second, which relates to the effects of pile engines, and appears to need revision.
Dr. Hutton bas long been the most popular of all our mathematical writers, and the perusal of these volumes has convinced us, that there are obvious reasons for this popularity, which promises to be as permanent as it is extensive. He seems to have a constitutional, if not a conscientious, aversion from the pedantry and parade of science. He never, by affecting to be abstruse, becomes obscure: nor does he ever slide into digressions, for the purpose of shewing how much he knows of other things besides the topic of discussion. Hence he is at once concise and perspicuous. He manifestly rather writes to be useful than to obtain celebrity. He is also perpetually aiming at improvements in every thing which he has undertaken. Whoever has occasion to compare the successive editions of his · Course of Mathematics, will find that the work was not abandoned to its fate as soon as its fame was established; but that it has been constantly modified wherever it was susceptible of improvement. Nor was this merely a habit of the prime of life : for, on comparing the solutions now given to some problems on his favourite subject of projectiles, with those which had previously been inserted in the third volume of the Course composed by Dr. Hutton in conjunction with Dr. Gregory, it will be seen that his mind has, in this respect, lost nothing of its vigilance, energy, and perspicacity.
Art. X. The Life of John Knot, containing Illustrations of
the History of the Reformation in Scotland, with Biographical Notices of the principal Reformers, and Sketches of the Progress of Literature in Scotland, during a great part of the Sixteenth Century. By Thomas M'Crie, Minister of the Gospel. Edinburgh. K NOX was one of those characters, who from their spirit and
genius, the impetuosity of their tempers, and the eventful times in which they lived, are rarely spoken of, even at a distant period, without extravagant panegyric or unqualified obloquv. This is peculiarly the lot of those who have signalized themselves as the leaders in religious commotions. The object is momentous,
and the passions are agitated in proportion. On one side ar arranged self-interest, ancient prejudice, possession, prescription, authority; on the other the most animated and animating of haman principles, conscience newly awakened, a sense of usurpabon newly acquired, disdain of fetters which are beginning to fall off, and the pleasure of defying those whom men have been accustomed to reverence. Hence in every cause and on every scale, from the petty but cannibal feuds of Egyptian fanatics to the mighty contests of the League and of the Crusaders, religious warfare has been conducted with a rancour peculiar to itself. But, as the weapons of this warfare are the tongue and the pen, as well as the sword, as the passions are thoroughly inflamed, and possessed of all the powers of giving vent to them which exasperated eloquence bestows, who can wonder that, during the beat of the contest, and even after it has ceased to be felt, otherwise than in its effects
, the characters of the great leaders of either party continue to be distorted by panegyric and detraction;--who can wonder that the cool impartiality of later historians finds no small occupation in removing the varnish or washing away the stains, or that acutefeas the most penetrating and inquiry the most impartial sometimes fail in detecting so many misrepresentations? It is strange, however, that, at the distance of no more than two centuries and á half
, with abundant materials, and after the elaborate investigations of many ingenious men, it should still be controverted whether the Regent Murray were a tyrant or a patriot, an hypocrite or a saint, or even whether Knox himself were a furious and ambitious demagogue, the enemy of every thing elegant and sacred, or an intrepid and disinterested champion of truth and liberty. To determine points of so much importance to the church of which Knox was the founder and Murray the nursing father, the present biographer has applied himself with a zeal and devotion, which, if they do not always serve the cause of truth, give a glow and an interest to the whole work, rarely communicated to biography
, when it did not breathe the spirit of personal friendship or domestic affection. But in treating this subject, a fatality seems to hang over its Scotish and even its English advocates. Passion and prejudice when applied to the History of the Reformation in Scotland, seem to be immortal, and the respective partizans enter upon their task with all the interest of agents, indeed of principals, in the story which they discuss. Some, and those in other respects of good understandings, seem to have been perfectly dementuted: all power of examining or comprehending evidence appears to have Hled before the vehemence of their feelings, and the little argument which they have been able to produce is suffocated beneath a load of passionate declamation and personal abuse.
The feelings and the prejudices of Dr. M'Crie are more chastized, and always uuder the command of a clear and strong understanding. A thorough Presbyterian in his religious principles, and a determined Whig in his politics, the colouring of his picture is always aggravated; the lights are heightened and the shades darkened by the prepossessions of his church and of his country: the outline, however, is not distorted. He is a warm, but an honest man. He is a Scotchman, but a friend of truth. With great powers of expression, as well as considerable heat of temper, he never descends to railing. He detests the church of Rome; he loves not the church of England; but he exposes the enormities of the former with fidelity and force, though not with malignity, and he censures what he conceives to be imperfect in the reforination of the latter, with an effect which would have been lessened by indecent invective. A vein of sarcastic wit alone now and then betrays him, as it did his master, into undue asperity as well as levity of expression.
These offences, however prompted by national prepossessions, however restrained by decorum, we scruple not to confess, would have been visited on the head of a dull or a shallow man with greater severity: for we too have our attachments, and even our prejudices; we love the constitution, we love the order and decency of the church of England: we prefer the beauties of our own liturgy to the best extemporaneous effusions of the wisest of the Scotish doctors: we see no connection between sordidness and devotion, nor should we have expected from a man of Dr. M'Crie's enlarged understanding so much of the spirit of old • Mass Jobn' buch indignation against a surplice or å rochet, things which, with our countrymen, not only have ceased to give offence, but have the great body of popular opinion in their favour. Still, however, to talents like his much will always be forgiven; and such are the merits of the work almost in every other particular, that we feel ourselves disposed, as far as justice will permit, to be blind or dumb to a single fault.
Dr. M‘Crie is really a great biographer, such as it has not been the lot of Knox's equals, or even his superiors, always to attain : for, however ably the characters of Luther and Calvin have been treated in the general bistories of their times, where has either of them found a biographer like the present? The Life of Erasmus, an animating subject and worthy of a man of genius, if any such there be within the compass of modern literature, has been frigidly written by Knight, and confusedly by Jortin; nay even in our present Number
we have an instance of a most original and strongly marked contemporary and countryman of our own, consigned to
prejudices greater than those of Dr. M‘Crie, prejudices chilled by mediocrity to which he is a stranger, while they are not redeemed by one of his excellences.
Compact and vigorous, often coarse but never affected, without tumour and without verbosity, we can scarcely forbear to wonder by what effort of taste and discrimination the style of Dr, M'Crie has been preserved so nearly unpolluted by the disgusting and circumlocutory nonsense of his contemporaries. Here is no puling about the interesting sufferer,'' the patient saint,' “ the angelic preacher. Knox is plain Knox, in acting and in suffering always an hero, and his story is told as an hero would wish that it should be told, with simplicity, precision, and force. Dr. M'Crie's materials are both ample and original: since beside an intimate acquaintance with the best authors who were contemporary with his subject, and the MS. authorities which the records of the church of Scotland afford, he has fortunately possessed himself of an early transcript of the reformer's letters, glowing throughout with the same ardent feeling of devotion, and the same unconquerable spirit of liberty, which animated his discourses from the pulpit. To these materials the author has brought a power of combining and enlivening them peculiar to himself. He has many points of resemblance to his subject: a fortitude of mind which on subjects exploded and derided dares to look modern prejudices in the face; a natural and happy eloquence, with a power of discussion on subjects of casuistry and of politics not inferior to that of the great leader in the reformation of Scotland, though restrained by a decorum of expression to which the reformer's age, as well as himself, were strangers. To these qualifications are to be added the same stern renunciation of all taste and elegant feeling, where they appear to stand in the way of duty, and the same tendency to coarse (or what would now be called illiberal) bunour on subjects where it is not altogether becoming. Like Knox himself he bas neither a tear nor a sigh for Mary, and we doubt not that like him he would have voted to bring the royal adulteress and murderer, for such they both esteem her, to the block. In Dr. M‘Crie the brutal merriment displayed by Knox on the assassination of Beatoun excites no indignation, and the old definition of such sanctified and sys. tematic murders, the execution of righteous judgment by private hands,' would probably be accepted without reluctance.
In a work so pregnant with original argument and reflection alınost every page affords matter for animadversion : but we shall content ourselves with detaching from the text a few of the most prominent passages, and commenting upon them en pussant, • Writers unfriendly to our reformer have endeavoured to fix an