neighbourhood; in which above eleven thousand perfons had
taken refuge, when this blood-thirty favage appeared before
their gates, and fummoned them to furrender. Here, defpair
would have induced them to defend themselves to the laft extre-
mity; but their commander, intimidated by the threats, and
deluded by the promifes of Gouda, entered into a capitulation,
and opened the gates, on condition that the lives and properties
of the befieged fhould remain inviolate. Yet no fooner had
this faithless victor got poffeffion of the town, than he ordered
the commander to be flayed alive, his wife and children to be
murdered, with circumstances of barbarity too fhocking to re-
late; and all the inhabitants to be maffacred, without diftination
of age or fex. To fatiate his own cruelty, he commanded all
the children, under five years of age, to be brought to him in
the balcony of the town-house, where he flaughtered above
eight hundred of these innocent victims with his own hands.
Similar enormities were committed by his adherents wherever
they came; and that part of the Ukraine which lies between
the Niefter and the Bog, was the fcene of every kind of defola-
tion that fire and fword, under the direction of the most un-
relenting and wanton inhumanity, can inflict. At length
Gouda became the victim of his own vanity: while he was
attempting the fiege of Dulczin, a Ruffian officer, who com-
manded a fmall party detached by Marfhal Romanzow, per-
fuaded him that the Empress of Ruffia, informed of the glorious
fuccefs of his arms, wifhed to make an alliance with him; and,
with this view, had ordered the detachment to join him. Gouda
fell into the fnare; and the officer, under pretence of concerting
a plan of operation, led him into an ambufcade of the Poles,
where he and eight thoufand of his followers were furprised
and made prifoners. They were all publicly condemned and
executed.

Some of the nobles of the Ukraine have, at length, per-
ceived the wisdom and good policy of encouraging manufac-
tures and trade, for which the country is advantageously fituated.
On this fubject M. HAMMARD's details are ample and intereft-
ing to those who wish for information of a commercial nature.

ART. V.

Sow.

HENRICI ALBERTI SCHULTENS-Oratio de Ingenio Arabum, &c.
i. e. An Oration on the Character and Genius of the Arabians.
By HENRY ALBERT SCHULTENS, Profeffor of the Oriental Lan-
guages in Leyden; delivered on his refigning the Rectorship of that
University. 4to. PP. 35. Leyden. 1788.

IN

N this judicious and elegant piece of criticifm, the orator's defign is, to recommend that branch of fcience in which he is fo defervedly eminent; and in which it is his province to

inftruct

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inftruct his hearers. He introduces his fubje&t by an applica tion of the maxim of Horace;

Eft modus in rebus, funt certi denique fines,

Quos ultra citraque nequit confiftere rectum.

And he obferves, that the little attention generally paid to the ftudy of Arabic, may, in a great measure, be ascribed to the violation of this wife maxim, by thofe who are enthufiaftic admirers of that language, and the works extant in it, as well as by those who, by affecting to treat both with contempt, endea vour to excuse their own want of application. The arguments of the latter class are by no means formidable, as it is ealy to refute that calumny, which has its fource in ignorance and indolence; but it is difficult to recommend the object of exagge rated praise to the attention of the unprejudiced and impartial enquirer.

In forming an estimate of the literary works of any people, it is proper to attend to the influence of their national characteri and manners on their studies and purfuits. This, the Profeffor thinks, has been too much neglected, and therefore he propofe: to confider, in this point of view, the Arabs who lived before the Mahometan Æra; in order to fhew the conformity of their national character to that kind of knowlege which was then cultivated among them.

But, though the exigencies and pursuits of a people are determined by their national character, yet this has alfo its caufes, on which it depends for its various modifications and degrees of activity thefe caufes are either natural, as bodily conflitution, climate, or age; or political, as form of government, language, education, manners, religion, and commerce with other nations. The Profeffor has briefly, but judiciously, examined the influence of each of these circumftance, in forming the character of the Arabs, which, he concludes, is exactly conformable to the divine prediction concerning Ifhmael, in Genefis, xvi. 12. and admirably illuftrated by the fublime defeription of the Onagi, or wild afs, in Job, xxxix. 5. Such, to this day, is the charac ter of the roving Arabs, who conftitute the moft confiderable part of the nation. Their hiftory abounds with inftances of kalted virtues, and of atrocious crimes. They are remarkable for their hofpitality, generofity, and inviolable fidelity; but these, as well as their capacity, cruelty, and love of revenge, are the confequence of their national manners and mode of lite: Their virtues therefore are not the fruit of philofophical culture, but the fpontaneous produce of nature; but with refpect to promptitude and magnanimity, they infpire a vigour of exer tion, which more refined manners feldom confer. Irrefolution fuits not the difpofition of an Arab. He never hesitates long, whether he hall perform a kind office to a friend, or shed the

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blood of an enemy. If an opportunity offers of doing both, it renders him completely fatisfied; but, if the gratification of his revenge happens to come into competition with an act of generofity, he will inftantly give the preference to the latter, and derive a pride from the confcioufnefs of having done his duty. To exemplify this, the Profeffor relates the following ftory:

Haffan, the Scenite, hofpitably received into his tent, Ibrahim, a chief of a neighbouring diftrict, who, driven from his country, was obliged to feek thelter in the defert. After some days fpent in cheerful feftivity, the ftranger, wishing to depart, requested his hoft to accompany him a part of his way. The latter confented; but, while preparations were made for the journey, he examined his lance with peculiar attention, and his eyes glowed with anger and revenge, as he eagerly sharpened his fword. "Thou feemeft," faid Ibrahim, to thirst for blood. Who is thine enemy? He fhall be mine."-" That tyrant, Ibrahim," anfwered Haffan," who fhed my father's blood. His power has long fcreened him from my revenge; but now he is a wandering exile, I will not reft till I have found him."-" Thou haft found him!" was the reply; "I am the wretch who killed thy father: behold in me the object of thy vengeance!"—" Thou, Ibrahim? by Alla and his prophet!But, thou art my gueft! I had fet apart this money to provide for thy journey. Take it while thou mayeft, and go thy way."

From a people thus circumftanced, the Profeffor observes, no great proficiency in arts or fcience could be expected; and when, in later ages, under the dominion of the Caliphs, they were excited, by honours and rewards, to fuch ftudies, the native fire of their genius, though it could not be entirely extinguished, was damped by the influence of tyranny, fuperftition, and luxury. Hence, though the prefent, with respect to learning and learned men, might be ftyled the golden age; yet the diftinguishing and characteristic merit of the Arabs must be confined within thofe periods, in which their genius was the untaught but vigorous offspring of nature.

In the remaining part of this oration, M. SCHULTENS briefly infifts on the peculiar fitnefs of their language for poetical expreffion, on their natural turn for eloquence, and paffion for poetry; together with the circumftances by which thefe qualities were cherished, and the objects by which they were excited; but, as his ideas on thefe fubjects are coincident with thofe of the best modern writers, among whom we may mention Sir William Jones and M. Herder, we fhall here clofe this article, by acknowleging the entertainment which we have received from perufing the work. Sow.

APP. Rev. VOL. LXXX.

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ART.

ART. VI.

Lettre de M. VAN MARUM à Monf. le Chevalier MARSILIO LAYDRIANI, &c. i. e. Letter from DOCTOR VAN MARUM to the Chevalier MARSILIO LANDRIANI, containing a Defcription of Electrical Rubbers of a new Conftruction. 4to. 8 Pages. Haarlem. 1789.

Otwithstanding the many improvements made, within a few

NOLW years paft, in the conftruction of electrical machines, much

remains to be done, in order to bring them to that degree of perfection, of which we may fuppofe them capable. For refearches of this nature, Dr. VAN MARUM is advantageously circumftanced, from his having the direction of the largest and mct powerful apparatus hitherto known *. In performing experiments with this machine, he found that the effect of it, when ftrongly excited, was confiderably diminished by the return of the electric fluid to the anterior part of the rubber. This inconvenience was before noticed, in the Philofophical Tranfac tions, vol. LXIII. by Dr. Nooth, who there gives fome direc tions for its removal. See Review, vol. LI. page 223. On thefe hints, Dr. VAN MARUM has improved; and, after a great number of trials, has conftructed rubbers which are free from this fault, and which, therefore, produce a much greater effect than the fort commonly used.

In the defcription of his rubbers, the Doctor is exceedingly minute; but, without a plate, it is impoffible to give our readers any other than a very general idea of their conftruction. The pair, here described, were made for a machine with a glass place thirty-two inches in diameter, and are ten inches long: the furface in contact with the glafs, is of oiled filk, which, about an inch from its pofterior edge, is covered with a thin fmooth coating of amalgama: this is made to preís equally in all its points on the glafs, by a parallelopiped of wood, formed as exac and smooth as poffible, which the Doctor calls a Prefer, and which is covered, on the furface toward the rubber, with the thickeft filk velvet that can be procured. The preffers are connected, by means of a hinge in the middle of the back of each, with a pair of strong fprings, which, at their oppofite ends, are each joined by another hinge, to a brass plate, and thus regulated by a fingle fcrew, placed between this and the circumference of the glafs plate. The oiled filk is cut nearly fquare, about twelve inches each way; and its amalgamized part is faftened to a brais plate on the pofterior edge of the preffer, but fomewhat longer than this; and into its further end, is fixed, at right angles with it, a rod of the fame metal, on which the infulating part of the filk is extended parallel to the furface of the excited glafs, fo

* See Review, vol. lxxiii. p. 551.

as to adhere clofely to it, without being rumpled by the rotation of the machine.

In these rubbers, it is of importance that the oiled filk be very fmooth, and free from all irregularities of furface, which not only impede the equal friction of the amalgama against the glafs, but also prevent the infulating part from adhering fo clofely to the excited furface, as is neceffary to hinder the electric fluid from returning to the rubber: the filk which the Doctor ufes, is made at Leipzic.

Of like importance is it, that the coating of amalgama, laid on the exciting part of the filk, be very thin and smooth; on its anterior part, its thickness fhould gradually diminish fo as that its edge may be fcarcely perceptible. Dr. VAN MARUM ufes the amalgama recommended by Baron Kienmayer of Vienna, which is preferable to any hitherto known: it confifts of one part of purified zinc, one of tin, and two of mercury. The zinc and tin are melted in an iron ladle, and the mercury added to them, as foon as they are taken off the fire: the mixture must be stirred with an iron fpatula, and, when cold, reduced to a very fine powder, in a glafs or marble mortar. Some varnish being laid on the filk, this powder is fprinkled on it, by means of a fine fieve; and, when dry, that which adheres is polifhed by rubbing it with a fteel burnisher; after which a drop of sweet oil is laid on its furface.

The Doctor compared the effect of his new rubbers with that produced by the common fort, by examining the number of revolutions which his machine required, with each kind, to charge a jar, containing a square foot of coated glass, to a certain height, determined by Lane's electrometer; the balls of which were, in these experiments, fixed at half an inch diftance. This, with a pair of his old rubbers, was effected in feven or eight revolutions; and, with thofe here defcribed, in one revolution and an half; with these alfo, the jar difcharged itself, on the ball of the electrometer, ten times in fixteen revolutions, to effect which, with a pair of the common rubbers, above eighty were required. A battery of fifteen fquare feet of coated glass was charged, so as to explode fpontaneoufly in fixteen revolutions, with the new rubbers; and the Doctor found, by his papers, that, in frofty weather, with Teyler's grand machine, which has four pair of common rubbers, he did the fame in eleven revolutions; and the degree of the charge, in both experiments, being determined by the fame electrometer, was exactly the fame.

Dr. VAN MARUM acknowleges that his rubbers are much more expensive than the common fort, and require greater care in their application and ufe; that the ftrong preffure of the rubbers, and the close adherence of the oiled filk to the glass, render

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