"Dr. Wollaston also was an original subscriber, and lent his name and high authority to the undertaking, whilst he lived.

"The work, as has been stated, commenced in 1825, but was stopped in 1828, by an irruption of the Thames.

"From that time to the spring of 1835, no progress was made. In this year, under the sanction of an Act of Parliament, the Treasury allowed the Exchequer Loan Commissioners to advance, out of the grant voted for public works, the money necessary to complete the Tunnel; and it was again commenced, and has been continued, with few but inevitable interruptions and delays, to the present time, when, as the Directors have stated, it is securely completed, and is about to be thrown open as a thoroughfare for foot passengers. The two roadways, for carriages under the river, are also perfectly completed.

on.

"From its commencement to the present date there have been but eleven years within which the excavation could be carried And during this time, for nearly two years or ninety-nine weeks, the works were suspended, from circumstances beyond the control of either the Directors or the engineer.

"When the public money was advanced, the practicability of the work was considered so doubtful, that it was made a condition, by the Treasury, that the most hazardous portion of it should be completed first, and before any expenditure upon any other part of the work was to be permitted.

"The Tunnel was therefore necessarily constructed in a line from the place of its commencement, viz.-from Rotherhithe to Wapping, under the bed of the river, as the whole of that portion of the work was deemed the hazardous portion. Hence no preparation could be made on the Middlesex side, either by the purchase of property, or the building of the shaft, &c., for descent.

"But what rendered this condition, annexed to the grant, of more serious importance was, that the engineer having found, from experience, it would be economical to work occasionally at both ends, alternately or at once, was unable to do so.

"It was found that the ground, through which the excavation had to be carried on, varied greatly: sometimes it was dense, and comparatively free from water, when the excavation could be carried on safely and expeditiously; at others, it was merely a loose river deposit, which had to be subjected to great pressure, by throwing gravel and clay upon that part of the bed of the river under which the work was being constructed, and allowing a heavily-laden vessel, adapted to the purpose, to settle over the shield. During this time, the whole establishment was at a stand still, adding largely to the cost and the time necessary for the completion of the work. Nor was the delay and the conse

quent loss of the expense of the establishment the only loss sustained. The machinery became injured and deteriorated, and had to be frequently repaired and renewed.

"All these circumstances were represented by the engineer to the Directors, and by your Directors to the proper authorities; but so uncertain was the completion of the enterprise considered, even up to the line of low-water mark, that it was not deemed right to advance, at any one time, more money than was required for the immediate continuation of the structure under the river.

"It is far from the desire of the Directors to make any complaint of the rule thus laid down, and with which the Proprietors have been before acquainted, and which the difficulty and novelty of the undertaking undoubtedly suggested; but it serves to show how strong was the conviction of the impracticability of the work, and also to account (which justice to the Directors and engineer requires should be stated) both for a longer time elapsing and a larger outlay taking place, than would have been the case had ample capital been at their disposal, to be applied according to their judgment and that of their engineer.

"The extra cost to the Company, during these periods of suspension, has been very little less than £40,000. in the whole. This sum, added to what remains undrawn of the sum the Directors were empowered to borrow, under their Act of Parliament, (viz. £30,000.) would go far towards the completion of the descents for carriages, even upon the present plan, enlarged as it was after the original dimensions and estimates were formed.

"Under these circumstances, adverse as they may be considered, and with a rigid economy carried often to the very verge of prudence, the work has been in fact executed in about nine years of actual work, at a cost of about £446,000, including property and expences of every description, with the particulars of which the Proprietors have been accurately and annually acquainted. The actual Tunnel of 1200 feet was executed in eight years.

"In the time stated, the whole work might easily, indeed more easily and safely have been accomplished, if, as has been explained, the requisite command of capital and its application had been obtained.

"The carriage-way descents are now alone wanting to complete the work. They are susceptible of being contracted for in the ordinary way; and your Directors propose, so soon as the foot thoroughfare is opened, to turn their attention to this portion of the work. It may require a new Act of Parliament; and your Directors recommend the Proprietors to invest them with a similar discretionary power to that granted on a former occasion, previously to the resumption of the work in 1835, in order to mature

such arrangements as may be necessary for the full completion of the work, and to determine upon its expediency with reference to the amount of capital required, and the probable return for it: which plans, previously to their adoption, your Directors will, as before, submit to the Proprietors at a Special General Meeting to be called for that purpose.

"Your Directors are of opinion, that without the carriage-way descents (the two roadways for carriages under the river being already completed) are added, a considerable amount of toll will be lost to the Proprietors and the Government.

"For foot-passengers your Directors have fixed the toll at one penny per passenger, and which they hope the Proprietors. will approve.

"The Directors propose, immediately on opening the Tunnel, to devote their attention to finally settling the cost of the permanent establishment, upon the most economical footing possible.

"They cannot conclude their Report without renewing an expression of their admiration of the ability of their engineer, Sir I. Brunel, who, in addition to the block machinery at Portsmouth, and the works in Chatham Dock Yard, now leaves another lasting memorial of his genius to this country. They desire also to acknowledge the zeal with which he has been seconded by the acting engineer, Mr. Page, and especially by Mr. Charlier, their clerk, in another department of the undertaking.

"Statements of the receipts and expenditure of the Company, for the year which ended the 31st of December, 1842, have been prepared, and are now submitted for the information of the Proprietors."

Thames Tunnel Office, Walbrook Buildings, 7th March, 1843.

BENJAMIN HAWES, CHAIRMAN.

AERIAL STEAM CARRIAGE.

It is much to be regretted that men of letters connected with the periodical press, to whom the public naturally look with confidence for information upon all subjects of notoriety, should generally betray such extreme ignorance of the elementary principles of science, and even of the established laws of nature, as to give countenance to any absurd scheme that may arise, and present to the world, with vaunting pretensions, projects the most visionary and fallacious.

Under this designation, we have long felt satisfied that the proposed aerial machine must be classed; and we have seen,

with no small degree of astonishment, not only that many intelligent and highly respectable persons have been induced to listen coolly to this wild project, but also that Parliament has condescended to entertain a Bill for forming a joint stock company, to carry this wonderful chimera into active existence.

We have delayed the publication of the present number of our Journal, in order to inspect and give a report of the specification of this invention, which has been just enrolled; and to discover, if possible, some new feature which might give colorable plausibility to the project; but no such feature is there developed. Time and space will not allow us now to detail the full particulars of this proposed machine; we say proposed, because no such machine has yet been made, or is, as we think, likely to be constructed, when its elements are understood by persons of com

mon sense.

The apparatus consists of a car, containing the goods, passengers, engine, fuel, &c.; to which a rectangular frame, made of wood or bamboo cane, and covered with canvass, or oiled-silk, is attached; this frame extends, on either side of the car, in a similar manner to the out-stretched wings of a bird, but with this difference, that the frame is immoveable. Behind the wings are two vertical fan-wheels, furnished with oblique vanes, which are intended to propel the apparatus through the air. These wheels receive motion through bands and pulleys, from a steam or other engine, contained in the car. To an axis at the stern of the car, a triangular frame is attached, resembling the tail of a bird, which is also covered with canvass or oiled-silk; this may be expanded or contracted at pleasure, and is moved up or down, for the purpose of causing the machine to ascend or descend.Beneath the tail is a rudder, for directing the course of the machine to the right or to the left; and, to facilitate the steering, a sail is stretched between two masts which rise from the car.

The amount of canvass or oiled-silk, necessary for buoying up the machine, is stated to be equal to one square foot for each half pound weight, the whole apparatus being about 3000 lbs., and the area of surface spread out to support it, 4500 square feet, in the two wings, and 1500 in the tail,-making altogether 6000 square feet. The engine is proposed to be of from 25 to 30 horse power. It is stated in the specification, that on launching the machine into the air, an elevated situation must be selected, and the machine allowed to run some distance down an inclined plane, for which purpose vertical wheels are attached to the bottom of the car or boat. When the machine has thus acquired a momentum, the rotary fan-wheels are put in action to raise it into the air and propel it; the rudder, appended to the car, is then used for regulating its course.

In concluding our hasty remarks on this invention, we would remind our readers, that many projects of a like character have been promulgated to the world by enthusiastic projectors, all of which have fallen to the ground, (we use a figure of speech, for they have never risen,) from the fact of having overlooked the laws of matter, and miscalculated the powers of mechanism, in imitating the functions of animal life.

REPORT OF TRANSACTIONS OF THE INSTITUTION OF CIVIL ENGINEERS.

(Continued from page 149, Vol. XXII.)

June 14, 1842.

The PRESIDENT in the Chair.

"On Iron Sheathing, broad-headed Nails, and Inner Sheathing for Ships."-By J. J. Wilkinson.

These three papers complete the subject which the author commenced in the year 1841, and continued during the present session.

The first treats of the use of beaten iron, and iron nails, even in very ancient vessels, their corrosion, and consequent abandonment; the attempted introduction of rolled iron for the purpose of sheathing. It touches lightly on the construction of iron vessels, and on various attempts to protect them, which experience has now shown to be unnecessary, as the first iron steamer, built by Mr. A. Manby, in 1821, at the Horseley iron-works, has been in constant use on the river Seine up to the present period, without showing any symptoms of oxydation, although the only precautions taken, have been to apply a coat of pitch, as often as to a wooden vessel. Extracts are then made from Mr. Grantham's treatise on "Iron as a material for Ship-building." A list is then given of the patents connected with iron sheathing, and the various modes of preserving it from corrosion, alluding particularly to the valuable labours of Mr. Mallet (of Dublin) on this subject in the archives of the Institution.

The next division treats of metallic sheathing, or a coating of metallic oxide, formed by driving broad-headed nails nearly in contact with each other, into the sheathing board; this process is called filling. The nails used for this purpose by the Romans, were of the form as those of the present day. There are authentic records of "filling" being generally in use in this country