the junctures between the component parts of the entire dam, or of each separate portion of it, may be made water tight, previously to its being put in its place; and in such manner as that, with the exceptions to be specified, it may be made to serve again for a similar purpose without separation of its component parts. The lower part of the dam is to be formed in such a manner as best to penetrate the ground on which it is placed, and to a depth sufficient to prevent the passage of water under it. Sometimes this under part is so formed as to be readly separated from the upper part, for the purpose of leaving it in the ground To protect the foundation of the work. The dam itself is to be forced into the ground by the application of weight, either with or without percussion, as the case may require. When the dam has answered its purpose in one case it may be removed and made use of in another, the lower part having been left behind, or not, as circumstances may render it

necessary.

Several distinct cases are given in this specification. The first is, when the space from which the water is to be excluded is circular, the dam should also be circular, exceeding in size the intended column of masonry, as much as will allow sufficient space for the workmen. The dam is to be formed of wooden staves, nine inches thick at the bottom, and tapering to three inches at the top, connected on the inside by rings of cast-iron, and so fastened as to admit of the dam being separated into two parts, so as to allow of its being taken away when the work is completed. To the lower end is fixed a ring of cast-iron about two feet deep, one inch thick at the top, and as thin as it can be well cast at the bottom, but strengthened with brackets three feet asunder. This dam is calculated to float about seven feet out of water, that it may the more easily be brought over the spot where it is to be set on the ground. Being adjusted as to its exact situation, plat. forms may be laid upon the interior rings, and weights laid upon them, whe ther of the materials to be used for the column, or any other description of weights, so as to press the cutting edge of the cylinder into the ground; and, when the edge shall have penetrated sufficient ly to have become water-tight in the ground, the interior water may be pumped out, the ground prepared in any manner that may be thought proper, and

the masonry proceeded with. The column being completed, the parts of the dam may, by unscrewing, or other means, be detached from each other, so that they may be removed without impediment from the column within. The cutting edge of iron may also be detached and left in the ground if thought requisite; or it may, together with the cylinder, be raised up out of the ground by means of screws, or other mechanical powers. The parts may then be floated to a conve nient place for reconnecting them, and for adding a new cutting edge if the first has been left in the ground.

It is not necessary to proceed through the other cases, which are but variations of the same principle; but it is observed, that an embanking wall may be carried on under the protection of a double dam in the following manner: the outer side of the dam being formed double, and one end being joined on to the part of the wall already built, the other end may be joined water-tight against the shore, either completely by a portion of a double dam, or in part by such a double dam, and the remaining part in the usual manner; or, if the distance be small, the whole of this end may be formed in the usual manner. "For the purpose of excluding the water from so extensive a space as would be required for the formation of a dock, or a great length of pier, &c. then any such line of dam might be formed by any number of such floating dams set one end to the other lengthwise, taking care in all cases, when shoring for this purpose would be inconvenient, to make the bottom or base on which such double dam is to stand of sufficient breadth to enable it to resist the pressure of the exterior water. The dams themselves might be made of wood, or of iron, cast or wrought, or of any other suitable material; and the double dam, being hollow like vessels, may be made use of as receptacles for materials, the erection of a steam engine, lodgings for workmen, or any other purposes subservient to the carrying on of the work.

"For the purpose," says the patentee, "of enabling the juncture between the several portions of dams set up separately to be more easily made water-tight, when in their places, I prepare, when the exact line of juncture can be previously ascer tained, a groove in both surfaces of the dams that are to meet; otherwise in one of them, continuing the groove down to

the

the lower edge of the cast-iron, or other penetrating part of the dam, into which groove so prepared either a tongue of wood may be inserted in the manner which has been practised in regard to coffer-dams, or in some cases with better effect some elastic or plastic matter, such as oakum, moss, cut straw, with or without a mixture of earthy matter, may be rammed down from the top to their very lowest edge.

MR. WILLIAM HARDCASTLE'S, (ABINGDON, BERKS,) for Improved Cranes to prevent Accidents from the Goods attached to the Pulley overpowering the Person at the Winch, or in the Walking Wheel.

This improvement consists in causing the rope or chain employed in raising or lowering the weights to wind upon two cylinders of different diameters, or two cylinders of the same diameter, turning with different degrees of velocity, but contrariwise, the rope or chain winding on one cylinder, at the same time it unwinds from the other, so that a weight hanging by a pulley from the middle or bite of the rope or chain is raised or lowered by the turning of those cylinders; for it is evident that the larger cylinder, or that moving with the greater velocity, will take the rope or chain faster than the smaller cylinder, or that moving with the lesser velocity; and, since the two ends of the rope or chain fastened to each cylinder tend to turn them in opposite directions, and each sustains an equal weight, they counteract each other and balance the weight, which consequently cannot run down of itself; and thereby the utmost safety is obtained in raising or lowering it. One of the cylinders may be turned by hand with a winch, or by a walking or raising wheel, or by any other mode of applying power; the other cylinder is to be turned from the first by toothed wheels on the axis of each; to

give the respective and required velocities, the cylinders may be of equal diameter and the toothed wheels unequal, or the cylinders unequal and the toothed wheels, observing that the nearer the diameters and velocities of the cylinders are to each other, the greater will be the power of the machine, and the slower will the weights be raised or lowered.

Observations of the Patentee.-The ad vantage that will result from this improvement is principally safety; from the present constructed cranes, and particalarly those with walking wheels, the number of persons killed or maimed almost exceed credibility. Indeed, accidents from the working of cranes have hitherto been considered so much a matter of course, that one might conclude all prac ticable means of prevention had been tried without effect; for, notwithstanding the great mechanical improvements recently made in almost every kind of machinery, the present patentee is the first that has undertaken to construct cranes on a principle that will prevent the recur rence of those accidents; and he appears fully persuaded that a few minutes at tention to his specification will convince any person that, by adopting his improvement, all liability of accidents will be removed, insomuch, that a stranger, who had never before seen a crane, might be entrusted with the raising or lowering goods with the same safety as the most experienced workman; another advantage attending it is, that one person is competent to lower any weight, how ever great; for, though the weight cannot run down of itself, it will require very little power to turn the winch or walking wheel in order to lower it; any of the present constructed cranes may, at a small expense, be altered to work on the principle of the patent.

A model may be inspected at No. 90, Blackinan-street, Southwark.

MR

this new production. In order to judge by comparison, it should be recollected that Milton obtained, three times five pounds for his Paradise Lost; Johnson 15001. for his Dictionary; and Darwin 6001. for his Botanic Garden.

In addition to his new Elements of

General Chemistry, SIR HUMPHREY

DAVY has undertaken another work on the Elements of Agricultural Chemistry, being copies of those Lectures which he delivered with so much applause before the Board of Agriculture.

Messrs. SHEPHERD (of Gataker) and JOYCE (of Highgate) announce, in two volumes, an Introduction to a Systematic Education in the various Departments of Literature and Science, with rules for studying each, and references to approved authors.

Mr. OLDFIELD will publish early in November, a complete History of the House of Commons and Boroughs of the United Kingdom, from the earliest Period to the present Time, in four octavo

volumes.

Two volumes of the Sermons of the late DEAN KIRWAN are announced, with an Account of his Life.-Is it not an opprobrium on the Irish nation, that no applications of the Editor of the Monthly Magazine, nor any stimulus of public spirit, have yet led to the publication of Memoirs of the two Kirwans, of Mr. J. C. Walker, and of General Vallancy, four departed ornaments of literature and science, and four sons of which Erin ought to be proud; but whom Irishmen have suffered to sink into the grave without a tributary line either in verse or prose?

In like manner is it not a libel on the

public spirit of the English literati, that the first account of the life and discoveries of our own Cavendish has just been read by Chaptal, at a sitting of the National Institute of France?

Mr. SOUTHEY announces two volumes of prose Miscellanies, under the title of

ΟΜΝΙΑΝΑ.

At St. George's Hospital and Georgestreet, Hanover-square, a course of Lec. tures will recommence on Monday, October 5, on physic and chemistry, by GEORGE PEARSON, M.D.F.R.S. &c. &c.

The Rev. S. BARROW, author of the Young Christian's Library, &c. will publish, in a few days, a volume of Sermons for Schools. It will comprise one for every Sunday in the year; besides one for Christmas Day, Good Friday, Easter Sunday, and Fast Day; the whole selected and abridged from Horne, Blair, Seed, Gisborne, Enfield, Zollikoffer, Paley, Jortin, Porteus, &c. &c.

The following arrangements have been made for lectures, at the Surry Institution, in the ensuing season: Mr. COLERIDGE on the Belles Lettres to commence on Tuesday, the 3d of No

vember, and to be continued on each succeeding Tuesday. Mr.J. MASON GOOD, on the Philosophy of Physics, to com mence on Friday, the 20th of November, to be continued on each succeeding Friday. And Dr. CROTCH, on Music, to commence early in 1813.

Mr. FIDDLER, a captain in the Hudson's- Bay service, has communicated to Mr. Arrowsmith, the draught of the dis trict of country which lies between the rocky mountains and the great ocean, and between the latitude 52 and 46. It contains all the head waters of the Columbian River, a lake called, by Mr. Fiddler, Lean's Lake, a river running into it called Arrowsmith's River, and a river of magnitude called Wedderburn's River. The whole tract is inhabited by tribes of flat-head Indians, and one large extent is filled with wild horses. Mr. Arrowsmith purposes to introduce these discoveries into his General Map of North American Discoveries.

Mr. ARROWSMITH has just completed a new Map of Germany, in six sheets of double elephant, being the largest map of that empire ever drawn and published in England. Like all the maps of this eminent geographer, this new one is derived either from original or unquestionable and superior sources.

The same Geographer has for some years been engaged on a Map of England and Wales, in eighteen sheets, which, when put together, will be tea feet by twelve. Of this extraordinary map it deserves to be noticed that, it will contain at least a million of names, which is the more remarkable because the places enumerated in the Population Return, are only 15,741; and Capper's Topographical Dictionary does not contain above 20,000 places for the three kingdoms, although double the number contained in Luckombe's Gazetteer.

Mr. THOMAS THORNTON announces a new edition of the Works of Otway, in three volumes.

The rapid and successful extension of Bible Societies through the kingdom, is a feature of the age highly honorable, particularly at a time, when the AntiChristian spirit of Warfare is so predominant. Let us hope, however, that the former spirit is an indication of an abatement of the latter; and that the Christian spirit of pcace will soon be as widely spread as the sacred volume which incul cates it. Among the Auxiliary Bible Societies, our attention has recently been called to that for the City of LONDON, at

the head of which is the Lord Mayor; and that for WILTSHIRE, under the sanc tion of the Bishop of Salisbury.

We always record with pleasure, improvements in the typographic art. At this moment it is our duty to mention one made by Mr. THOMAS MOTTLEY, of Bristol, particularly useful for cutting large letters, and any kind of peculiar types in copper, called copper-plate printing types. The principle is likewise extended to the large letters used for signs, for which purposes the letters may be cut either in copper or iron. The inventor's London agent is Mr. W. Jenner, of Førster Lane.

The second volume of the Pulpit, by Onesimus, will be published in the course of the ensuing month; comprising Criticisms on Thirty-six Preachers, and Memoirs of the late Rev. Tho. Spencer.

The report of a Tourist among the booksellers of Great Britain, enables us to state that the increasing passion for literature operates in regard to the sale of books, as a counterpoise to the general dearth of trade; and that, among book. sellers, there have been fewer failures and less distress than in most other branches of our home trade. We pub lish this fact with exultation, not that we think any class of British society is, at this time, to be envied, but because it is encouraging to our views of the general progress of literature.

Mr. ADAIR, author of Questions on Goldsmith's History of England, has in the press, a similar collection of Ques. tions on Murray's Grammar, and Irving's Elements of Composition.

A small impression is reprinting of that extremely scarce book entitled, A Spiritual and most Preciouse Perle, teachynge all Men to loue and imbrace the Crosse, as a most swete and necessarye Thynge, with Preface, &c. by Edwarde, Duke of Somerset, Uncle to Kinge Edward VI.

stone was to common lawyers. Each of them simplified a complicated science; each of them analysed, and reduced to elementary principles, a mixture of he terogeneous particulars, but a continued succession of new statutes, enacted for the purpose of meeting new evils, not less than various new interpretations of old ones, have not only rendered repeated editions of these Treatises necessary, but have invited the investigations of additional writers; till it is become a matter of doubt, whether the actual execution of a magistrate's duty, or the fatigue of learning it through the medium of such voluminous instructions, be the more irksome task. To supply this defect, and at the same time to produce a work of practicable reference, and to condense, into the smallest intelligible compass, the voluminous information already in use, has therefore been the leading purpose of Mr. Dickinson's new produc tion.

Miss GRAHAME is printing a Journal of her late Residence in India, accompanied by illustrative engravings.

Mr. TABART, of Clifford-street, who had the merit of opening the first juvenile library, a species of establishment which has since had many imitators, is printing a revised and ornamented edi tion of Barbauld's and Trimmer's Les

sons.

The Rev. DAVID BLAIR, whose name is a passport into all seminaries, has just completed a Parent's Catechism of the First Dawnings of Knowledge; including, among other appropriate ornaments, a clock-face, with moveable dials, for teaching children the art of learning the hour.

Proposals, with annexed specimens, are at this time issuing gratis by the booksellers in town and country, for a subscription work intitled, Shakespeare set Free, or the Language of the Poet asserted; being a full but dispassionate examen of the readings and interpretations of the later editors. The whole comprised in a series of notes sixteen hundred in number, and further illus

his plays, to the various editions of which this publication will form a complete and necessary supplement.

Dr. ADAM'S Autunnal Course of Lectures on the Institutes and Practice of Medicine, will commence on Thursday, the 8th October, at his house, Hatton Garden.

Proposals have been issued for pub

lishing

Eshing by subscription, in ten Numbers, forming one volume, Specimens of the Architectural Antiquities of Norfolk; containing sixty highly-finished Etchings, representing exterior and interior Views of the most celebrated Remains of Antiquity in the County; accompanied with suitable Descriptions; by JoHN SELL COTMAN.

An edition of the late Mrs. COWLEY'S works, in three octavo volumes, is in a state of forwardness.

A new work will appear in October, upon the Prophecies, entitled "England Safe and Triumphant;" by the Rev. FREDERIC THRUSTON, M.A.

A posthumous work will speedily appear, by Mr. WILLIAM DAVIS, late editor of the Gentleman's Mathematical Companion, entitled Familiar and Complete Treatise of Land Surveying, by the chain cross and offset staffs, in four parts; to which is added a Supplement, containing the methods by the plane table and theodolite, with directions for conducting subterraneous surveys.

Sabrina island has gradually disap. peared since the month of October, 1811, leaving an extensive shoal. Smoke was discovered still issuing out of the sea, in February, 1812, near the spot where this wonderful phenomenon appeared.

The Carmarthen, on a late voyage from Port Louis to Bombay, in the early part of the monsoon, passing to the Southward of the Sychelles, fell in with a small low Island, which is not laid down in any chart or book. It runs from north-east to south-west, is about six or seven miles long, and one or two broad, lat. 7° 7' south, long. 53° 5' east.

It is a fact most disgraceful to the Le. gislature, the age, and the nation, that the Schedule to the new Medicine Act contains the names and titles of between FIVE and SIX HUNDRED QUACK MEDICINES! The principal object of the bill was, however, to render liable to the STAMP DUTY and REVENUE LAWS, "All artificial mineral waters, and all waters impregnated with soda, mineral alkali, or carbonic acid gas.

Mr. BRODIE has read a paper on animal heat, to the Royal Society, tending to confirm some of his remarks on this subject in his former communications. He animadverted on the inadequacy of Black's theory, and the inaccuracy of Crawford's experiments; showed that, by artificial respiration, animal bodies deprived of the brain cool faster than when left alone, although an equal portion of

oxygen is absorbed, and carbon disengaged in the process, as when the animal was living; and he hence inferred, that the action of the brain and nerves, is necessary to the production of animal heat. A Child under eight years of age has lately been exhibited at Spring Gardens, possessed of wonderful powers for performing arithmetical operations. His name is ZERAH COLBURN, and he was born at Cabut, in Vermont, in the United States of America, on the 1st of September, 1804. About two years ago, being at that time not six years of age, he first began to show his wonderful powers of calculation. His father, who had 'not given him any other instruction than such as is to be obtained at a small dayschool, was surprised one day to hear him repeating the products of several numbers. The news of this infant prodigy soon circulated through the neighbourhood, and the father was encouraged to undertake the tour of the United States, and finally to visit London, where they arrived an the 12th of May last. He determines, with the greatest facility and dispatch, the exact number of minutes or seconds in any given period of time. He tells the exact product ari. sing from the multiplication of any numbers, consisting of two, three, or four, figures; or, any number, consisting of six or seven places of figures, being proposed, he will determine, with expedition and ease, all the factors of which it is composed. This singular faculty consequently extends to the raising of powers, and to the extraction of the square and cube roots of the number proposed; and likewise to the means of determining whether it be a prime num ber. At a meeting of friends, this child raised the number 8 progressively to the sixteenth power, and, in naming the last result, 281,474,976,710,656, he was right in every figure. He was asked the square root of 106929, and, before the number could be written down, he answered $27. He was then required to name the cube root of 268,336,125, and with equal facility and promptness replied 645. One of the party requested him to name the factors which produced the number 247483, which he immediately did by mentioning the two nunbers 941 and 263; which indeed are the only two numbers that will produce it. Another of them proposed 171395, and he named the following factors as the only ones that would produce it, viz. 5×34279, 7×24485, 59×2905, 83X