Art. 74. A Defence of Itinerant and Field Preaching: preached be fore the Society for Gratis Sabbath-schools, 24th December, 1797, in Lady Glenorchy's Chapel, Edinburgh. By Grenville Ewing, Minister of the Gospel. 8vo. pp. 58. 18. Ogle. 1799.

The beautiful imagery of this writer's text (Prov. i. 21, 22.) is illustrated and exemplified daily, and its truth is continually estab lished. Wisdom, indeed, crieth without, she uttereth her voice in the streets, &c. Yet we can scarcely suppose that this preacher, a man of sense as he undoubtedly is, would explain metaphorical language, highly but justly wrought, in a literal manner; and hence extract an argument in support of the practice mentioned above. However, he proceeds to furnish a long list of street-preachers, &c. from the days of Enoch the seventh from Adam, to the time of our Saviour, and his apostles, with their contemporaries and successors, who were employed to disseminate the principles of Christian truth in a dark and ignorant world. When our field-preachers produce their credentials, and prove beyond a doubt, by miracles and similar testimonies, that they are divinely commissioned and inspired, we shall be constrained to allow them due attention: otherwise, we should apprehend that, in a country in which Christianity is known and professed, if the numerous body, to whose office it more directly belongs, applied themselves with assiduity to recommend and enforce its practical truths, the great and important ends of religion and virtue might be attained without much of this interference. Far be it from us to condemn, however, or rashly to censure, well-meant exertions to do good to mankind. Whether the class of men, whose cause is here pleaded, do generally and really understand Christianity; whether they do not talk much nonsense; or whether at least a great part of them do not preach John Calvin rather than Jesus Christ ;-these are questions, on a discussion of which we will not enter.

The reader will find in this discourse several judicious observations, and useful thoughts; and the author discovers some energy of language and of argument. The unfettered preaching of the gospel is an object for which he contends;--he discards a mere political religion, though we do not perceive that he objects to the trammels of creeds and confessions.

CORRESPONDENCE.

We are obliged by the compliment paid to us by J.; and, had we furtunately some of that leisure which he professes to enjoy, we wo duly attend to his lucubrations. As it is, we can only advise him to favor some respectable magazine with his remarks and observations

Other letters remain for consideration..

The APPENDIX to VOL. XXIx of the Monthly Review, N. S. will be published on the 1st of October next, with the Number for September, as usual.

TO THE

TWENTY-NINTH VOLUME

OF THE

MONTHLY REVIEW

ENLARGED.

FOREIGN LITERATURE.

ART. I. Nouvelle Architecture Hydraulique, &c. i. e. New Hydraulie Architecture, containing the Art of raising Water by means of dif ferent Machines; of constructing in that Fluid; of directing it; and generally of applying it, in different Methods, to the Uses of Society. The first Part containing a Treatise on Machines, for the Use of those who undertake Constructions of all Kinds, and of Artists in general.-Part II. containing a detailed Description of Steam-Engines. By R. PRONY, Member of the National Institute of Arts and Sciences, Civil Engineer, &c. 4to. pp. 823; exclusive of the Notes, Plates, and Explanations. Paris. Imported by De Boffe, Taylor, &c. London.

ALTHOUGH men are usually excited to particular studies by

circumstances which are accidental, or of little moment, rather than by any decision of the judgment after a careful examination of the advantages and disadvantages which each object of inquiry presents, yet are they eager and zealous in extolling their own pursuits and depreciating those of other people. Hence terms of contempt have been interchanged between the respective advocates for law, poetry, science, natural philosophy, &c. with little reason and less temper. That some pursuits are preferable to others is true, because there are some which are evidently frivolous, or followed beyond any object of rational attainment :-but, were the aim and tendency of every research in science and literature what they ought to be,-either mental instruction or mental delight, it would be difficult to say why one research was preferable to another; or to state arguments for the neglect of any study, which would not operate to its complete exclusion. APP. REY. Vol, xxix.

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Of the many and various arguments, however, to which pride and the fertility of invention have given birth, none seems to have gained a more general reception, than those which have been urged against pure and abstract science. The mathematics have been represented as most unfit for purposes of wealth, of enjoyment, or of ambition; as punishing students with languor and moroseness; rendering them indifferent, even as the gods of Epicurus, to all objects of human concern; exempting them from the influence of passion; and consequently suffering them to partake of a small portion only of the good and evil of life. The disciples of Euclid and Newton are not only not to be moved by trivial accidents and petty vexations, but are insensible even as Archimedes while the sword of death was descending on him.

These arguments, which are plausible because they are in part just, have been deemed incontrovertible by some who have not sufficiently considered the nature of the human mind, of abstract science, and of the true object of life; in general, too, they have been urged by men who have not been distinguished by variety, by extent, nor by accuracy of knowlege; by men who have neither added to truth, nor embellished it *. The defence of the mathematics has been rare, because the culti vators of this science have not been very ambitious of gaining the public suffrage in favour of its propriety and advantages: but the defence has been made: it has been urged that the mind has its wants, as well as the body; that the food of the mind is truth,-and that truth, genuine and sure, is to be found in the mathematics; that it is desirable to reason justly, although on frivolous subjects; and that the science, therefore, is worthy of regard, which gives to the mind a habitude of just argumentation, and renders it pliant to truth. On reasons like these, has the vindication of what may be called the spiritual and philosophical utility of the mathematics been conducted. Its gross and material utility furnishes a not less sure and ample ground of defence; and this ground is to be sought amid the variety of inventions which add to the comforts and luxuries of society, and amid those arts by means of which commerce is conducted with safety and expedition +. In this subserviency of speculative

Fontenelle says that "men, indulging a species of revenge, abuse what they do not understand, or what is hard to be understood; and the mathematics are difficult of access, thorny and arduous."

The following passage, from the celebrated preface to the Memoirs of the Academy of Sciences, illustrates and enforces what we have said:

culative truth to abstract good, in this investment of abstract conceptions with power, consists what Bacon calls, "the deep, fruitful, and operative study of the sciences ;" and indeed the advantages to be derived from the co-operation of scientific and mechanical ingenuity are too evident, and too demonstrable, to be denied. On this account, the impugners of the mathematics have. thought to deprive them of their fairest title and most weighty recommendation, by asserting that improvements in the mechanical arts rarely originate from merely speculative philosophers, but are due to the genius of mechanics who are unread and unlearned in the subtile, connected, and refined reasonings of an Euclid, a Newton, or an Euler. This assertion is indeed partly true: it is in a great measure warranted by experience, and may be made probable by an examination of the mental habits and modes of reasoning induced by the study of pure and abstract science.

Considering the truth of the assertion as established à posteriori, it may be observed that, although the examples of a Newton and a Galileo might be adduced, and of an Archimedes who rose from his figures to animate and direct powers which scattered dismay and ruin over the arms of the most warlike nation on earth, yet the great benefactors of the arts have been men who were not trained in all the discipline of

"We have a moon to enlighten us during our nights: of what concernment to us is it that Jupiter should have four? Why so many tedious observations, so many fatiguing calculations, to obtain an exact knowlege of their courses? We shall not be more enlightened; and nature, which has placed these small stars beyond the view of our eyes, seems not to have intended them for us. Influenced by reasoning so plausible as this, we ought to shun the observation of satellites with a telescope, and the investigation of their motions: -yet it is certain that we should thus be great losers.

"Whoever is even slightly acquainted with the principles of navi gation, and of geography, knows that, since the discovery of the four moons of Jupiter, science has been more benefited by them than by our own: that these moons serve, and will continue to serve, with increasing utility, to make marine charts beyond all comparison more exact than they were in antient times; and consequently to preserve the lives of an iniinite number of mariners. Did astronomy derive no other benefit than this from the satellites of Jupiter, it would be sufficient to justify those immense calculations, those observations so assiduously and so scrupulously made, this grand appa ratus of instruments, this superb building, devoted to the sole use of the science! In the mean time, the mass of mankind have no knowlege of the satellites of Jupiter, or such as is confused, and scraped up from common report;-or they are ignorant of the connection of these moons with navigation,-or even that in late times navigation has been rendered more perfect."

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severe reasoning, nor inured to the rigour of strict mathematical demonstration: but men possessing what is called natural sagacity, or a knowlege acquired irregularly, and with little formal study; who had not erected in their minds a gradual, regular, and connected system of truth, but had taken hints from common objects, and had derived their inventions from the forms of trees and the contrivances of animals.

To prove à priori that the most able geometricians are not likely either to invent or improve what is useful in the arts, we must advert to the criterion of beauty in mathematical science. This criterion requires that the principles, on which the reasoning is to be founded, should be few in number, and the most simple and obvious truths; that the demonstration should be connected throughout; that nothing should be assumed as axiomatical or evident, which admits of deduction from something more simple; and that the longest and most tedious operation is not to be shunned, in order to link together parts apparently but little disunited. Hence, he who loves to seek truth in abstract science combines slowly and scrupulously; examines an object on all its sides; makes only one step at a time; and makes that sure before he attempts a new one. To the inventions and improvement of machines, on the contrary, a different habitude of mind is requisite. Nature offers such a multiplicity and variety of circumstances, of which the separate and exact influence is unknown, that we cannot reason strictly from them, nor assign their precise effect. We should combine more rapidly, and comprehend more largely, if we would add to the inventions of art. The mind must quit its slow, scrupulous, and sure operations, in order to make a large and sudden grasp.

Although, however, men of. speculative research have not always been what Bacon says they ought to be," the guardians of those stores from which men in active courses are furnished," yet, of late years, it must be observed circumstances have determined them to apply their calculations to matters of practical utility. The forms of lenses, on which the perfection of telescopes depends, have been determined after an analytical investigation; the resistance and motion of fluids have been calculated; the figure of columns which support the greatest weight under a given volume has been assigned; and naviga tion has been most essentially benefited by the methods which have been invented for determining the longitude.

What degree of union has been already effected between science and experiment; what aid analytical research has given to mechanical contrivance, or may hereafter give; it is the business

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