I found it of great use in ascertaining at what depth sand sufficiently firm to build upon was to be found, as the soil of Berlin is chiefly composed of sand of various descriptions.

I remain, Sir, yours obediently, F. J. EVANS. Gas Works, Horseferry-road, Jan. 7, 1840.

NOTES AND NOTICES.

Flax Spinning at Amiens.-There is, at present, a joint-stock flax-spinning company at Amiens, at the head of the management of which was the late John Maberley, Esq., whose salary was 10001. per annum and the engagement for twenty-one years. Before his death, he had completed arrangements with an eminent flax-machine maker, in Manchester, to make the whole machinery on the spot, he (Mr. M.) being resolved that not a single machine should be imported from England. Mr. M.'s hatred to this country was known to be extreme. The master mechanist's agreement is a most beneficial one; for instance, if a machine cost, say 1004. at Leeds, and the carriage and commission 15 per cent., and the insurance against smuggling 30 per cent., then the price paid for the machine, at Amiens, was to be 145, or 50 per cent. above the English price. The number of spindles are understood to be 25,000. The two engines are by Mr. Fairbairn, of Manchester, and of eighty horses each. Another flax mill of equal magnitude was commenced at the same place in 1838, and is now fast progressing.-Sh field Iris.

To Crystallise Tin.-One spoonful muriatic acid, one nitric acid, eight water. Mix. Warm a piece of block tin over the fire, and rub it with a cloth dipped in the mixture. Ornament with coloured

varnish.-Mining Journal,

"Norwich a Port," a Failure.-The experiment of restoring Norwich to its ancient situation as a port, by making the River Yare navigable for seaborne vessels, does not seem to have been attended with the success merited by an undertaking so boldly projected and spiritedly executed. The whole of the works are now advertised for sale, not by the proprietors, but by government, under the powers of an Act for securing monies advanced for public works, by virtue of whose provisions the whole of the navigation has become forfeited for default of payment of interest. It appears from the particulars that the whole of the tolls on vessels navigating both the Yare and Mersey, the latter of which is available for vessels of 60 tons as high as Beccles, amount to little more than a thousand pounds per annum. The speculation must therefore have turned out a grievous failure, in spite of the flattering prognostics of success which attended its earlier stages.

Definition of a Mine.-A question has been raised, which will form subject for discussion in a court of law, as to the construction put upon the word "Mine," as applied to under ground operarations; it being contended on the part of some parties that the term "mine" is only applicable to mineral deposits, but which, we believe, has been already overruled--a "mine" being, in a legal sense, construed as applying to any excavation or underground operation, which may partake of workings carried on in a "miner-like manner." Hence, a qnarry, although not yielding mineral produce, will be construed as coming under the denomination of a "mine," that is, where levels are driven, drifts carried shafts or pits sunk, or machinery employed to either of the appliances whereby the material is obtained-such being the legal construction put upon a "mine." We are not prepared to say whether a quarry, worked open-cast, would come under this definition: our opinion is, decidedly not -but when worked by level, either on the bed or at a

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depth to intersect the same at a certain distance, or by shafts, no question, we consider, can arise but that the working is that of a "mine." As the matter will, in all probability, form subject, as we have already observed, for legal discussion and opinion, we shall await the result, when we may have to say something more, with references to cases already determined. In the interim we invite the attention of our correspondents.-Mining Journal.

New Overshot Water-Wheel.-The great overshot wheel, erected by the Kilgetty Colliery Company, at Merrixton, near King's Moor, Pembrokeshire, was set to work on Saturday the 7th ult., in the presence of a large assembly of the ladies and gentlemen in the neighbourhood. This wheel, we believe, is the most powerful in the principality, being of 75-horse power; the diameter is forty-feet, and it is seven feet wide on the breast, and the buckets hold water more than one-third of the circumference. It is fixed in a manner that is quite novel in this country, the wheel being so closely shut in by finely-executed masonry, that the escape of water, without going to the buckets, is impossible. It works by eccentrics, giving a horizontal motion to the cranks, being the first application of this mechanical arrangement to such a purpose. It is adapted to work two pumps, giving twelve strokes a minute to each pump. The water is diverted from the stream about two miles from the wheel, and it is brought to it across the valley by an aqueduct, extending 300 feet in length, and from thirty to forty feet high. The wheel will supersede the use of steam power in the colliery, and it is contrived that, in time of drought, the water to be raised by the wheel will assist to drive it. The whole arrangements of the wheel are new applications of mechanism, and great improvements on plans hitherto in use. Considerable attention has been given to these works by parties who are not interested in them; and in the immediate neighbourhood, where so much enterprise at the present moment is in active operation in mineral undertakings, they well deserve the attention of all parties engaged in such enterprises. The works are close to the new road leading to Hobbs' Point, and may be conveniently inspected by parties travelling that way. The wheel and machinery were designed and executed by Mr. Thomas Dyson, of Downham, in Norfolk, where the wheel was made, and he has personally superintended the execution of the whole work. Although the wheel was made in order to drain the mine by pumps, it is understood the parties have since been advised to try instead the patent hydraulic belt, and intend to adopt it. A model was exhibited, and excited much surprise at the simplicity of the effective mode to raise water it had on a small scale.-Cambrian.

Gates for the Crossings of Railways.-Mr. T. Lambert of Stockton-upon-Tees, has constructed a neat mode for gates, to be used at the crossings of railways. The gates turn on centres; and are so simple and complete, that one man can open both of them at one time with the greatest facility. When open, they prevent any one passing on the railway, and admit the progress of carriages, carts, etc., on both sides of the turnpike. Each gate is also furnished with an elevated circular signal, containing a lamp, which turns with the gate, so that whether it be night or day, persons at a great distance will be enabled to see when "danger" is announced. We have had the pleasure of examining the model, and can say with truth, that the invention seems to effect every thing necessary for the protection of life and property at crossings, while it allows the greatest facility for passing on the road.-Sunder. land Herald.

Leather Electrical Machine.-The Rev. Theo. Dury, under date of December 17, 1838, at Keighly Rectory, Yorkshire, England, communicates the following fact to Dr Faraday. He speaks of what he calls an extraordinary electrifying machine, which is no other than a leather strap which connects two drums in a large worsted mill in the town

of Keighly. "The dimensions and particulars of the strap are as follows:-It is in length, 24 feet; breadth, 6 inches; thickness, inch; it makes 100 revolutions in a minute. The drums, over which it passes at both ends, are 2 feet in diameter, made of wood, fastened to iron hoops, and turning on iron axles; these drums are placed at ten feet distance from each other, and the strap crosses in the middle between the drums, where there is some friction; the strap forming a figure of eight. There is no metal in connection with the strap, but it is oiled. If you present your knuckle to the strap above the point of crossing, brushes of electrical light are given of in abundance; and when the points of a prime conductor are held near the strap, most pungent sparks are given off to a knuckle at about two inches. "I charged," says Mr. D. "a Leyden jar of considerable size in a few seconds by presenting it to the prime conductor. The gentleman who told me of this curious strap has frequently charged his electrical battery in a very short time from it; and he informed me, that it is always the same, generating electricity from morning to night, without any abatement or alteration. If this strap had the advantage of silk flaps and a little amalgam, it would rival the machine in the lecture room in Albemarle-street.-Silliman's American Journal of Science and Arts.

Daguerreotype.-At the last sitting of the Academy of Sciences, M. Arago announced an important improvement in the process of the Daguerreotype. Hitherto it has been necessary, in order to give the gold-coloured coat of iodine to the silvered plate, to expose it for some length of time to the vapour of iodine in a box, in which the chemical substance was placed. By the new mode, instead of placing the iodine in the box, a plate is first impregnated with the vapour, and this is placed in a flat box within half an inch of the plate on which the drawing is to be taken. The box is then shut, and in two minutes the silvered plate has acquired the proper tint. M. Daguerre hopes soon to simplify the process of the mercurial vapour after the drawing in an equally satisfactory manner.-Galignani's Messenger.

Microscopic Institution.-Our scientific readers will be glad to hear that a meeting took place on Friday, the 20th ult., for the purpose of forming a Society for the Promotion of Microscopical Investi. gations, the introduction and improvement of the microscope as a scientific instrument, the reading and discussion of papers on new and interesting subjects of microscopical enquiry, the formation of a collection of rare and valuable microscopical objects, and a library of reference. The establishing of such a society has been long under consideration, and in September last a provisional committee was appointed to prepare an outline of a constitution. The meeting was numerously attended, Professor Owen, who was in the chair, was elected president; N. B. Ward, Esq., treasurer; and Dr. A. Farre, secretary. The constitution prepared by the provisional committee was unanimously adopted, and, at the close of the meeting, the president announced that more than fifty gentlemen had enrolled their names as members, and that the future meetings would be held at the rooms of the Horticultural Society.-Athena um.

Photography in India.-Photogenic drawing has been introduced into India, where it has attracted much attention, and where, certainly, so far as the action of the sun is concerned, there must be every facility for its execution. An improvement on M. Daguerre's practice has been invented at Calcutta by a Dr. O'Shaughnessy, who, instead of nitrate of silver, makes use of a still more costly material,-a solution of gold, by the aid of which he professes

to be able to produce drawings very brilliantly coloured, especially in shades of red, in purple, and even in green, which has hitherto been unattainable in Europe. The Doctor also avails himself of a lens which is said to impart all the effects of light and shade to the pictures produced. If one half of the Doctor's presumed success be real, his improvements well deserve, and will no doubt soon receive, the honours of importation.

Institutions of Liverpool.-A second Mechanics' Institution has recently been founded at Liverpool, for the benefit of the numerous bodies of working men inhabiting the northern divisions of the town, who, although Liverpool is not yet quite so large as London, found themselves too far distant from the already-existing institution to partake with facility of its advantages. The new establishment appears to be very spiritedly supported, and several courses of lectures (on scientific subjects, too,) have already been delivered. The "Mechanics' and Apprentices' Library" continues also on the increase, in the number of its books as well as members. Many valuable donations have just been made to its shelves-among others a complete set of the "Naval Chronicle," a work which, although not so indispensable as some to peaceful" mechanics and apprentices" on land, is yet well worthy of a place ⚫ in any general collection.

Steam Communication with India.-Much dissatisfaction has been created by the irregular manner in which the mails have been carried from India to Egypt by the East India Company, who take off the steamers from the line to serve any purpose of the moment, and regard the main object as secondary only to those of the company. The inhabitants of Calcutta have consequently held a public meeting to carry the object more completely into effect; but unfortunately, though the conduct of the company is reprobated on all hands, the dissatisfied seem to have split into two opposing bodies, so as most probably to neutralize each other's ef forts. One party is for supporting the company which has been formed in London, for establishing steamers by the Red Sea line, with Mr. Timothy Curtis at its head; the other proposes to raise a subscription at once, and build at least one vessel with Indian funds alone. It is much feared that, unless the two parties come to a compromise, the general cause will be injured rather than benefited, and that the service as performed by the East India Company will become more irregular than ever.

Gypsography.-This is the new title bestowed on the process patented by Messrs. Woone and Co., and heretofore styled metallic relief engraving. The name is derived from the "gypsum," or plaster of Paris, used in the first instance in the production of the design from which the cast for printing is made. The patentees have opened an establishment at Edinburgh, and announced their readiness to execute orders, and a musical work has actually been commenced, from gypsographic plates. The pro. cess appears to answer well for this style of work, but that, of course, affords no test of its capabilities for rivalling wood engraving in the higher branches of the art.

Errata in Mr. Holebrook's "Remarks on Mr. Rennie's Comparative Experiments on Propellers," inserted in No.856:-In line 8, col. 2, of page 227, abore is inserted instead of alone. At the end of the same page should be added the following words-effected, without increasing the quantity of the area of floats immersed. In line 4, column 1, of page 229, supposes should have been suppose. In line 16, from bottom of column 2, of same page, instead of wheels, it should be wheel. And in line 26, from bottom of column 1, of page 231, wheels should be read for wheel.