IRON PLATES FOR IRON-CLAD SHIPS.

An enormous furnace is erected, in which the iron is heated into a molten mass, and thence conveyed by steam-power in a truck on a tramway to the rollers, between which it is drawn out to the proper size and consistency. Previous to this, however, the metal has had to undergo an elaborate process. Originally each plate consists of 96 pieces, each about inch thick, and these are welded together one after another till they form either two or four solid lumps. In this state they are put into the furnace, and when the plate finally comes out from between the rollers it is only 4 inches thick. The power of resistance of such a dense mass of metal must be immense. Of course, the iron used is the very best. A plate of eight feet by six feet weighs about three tons.

The making of these plates has just been commenced in Sheffield, England, by Messrs. JOHN BROWN & Co., at the Atlas Steel and Iron Works, being the first manufacture of the kind in Sheffield. We understand that the plates were previously made at the Pargate Iron Works. Messrs. J. BROWN & Co. have been entrusted by the British government with a very large contract for the construction of these plates for the armor-clad war ships.

THE MAUVE AND MAGENTA COLORS.

This general term originates in the name of the inventor, Mr. W. H. PERKINS. In it are included Mauve, Magenta, Solferino, Azaleme, Roseine, Violine, Fuchsiacine, and those other beautiful varieties of color which are produced by our dyers in silk, wool or cotton.

We never before possessed any tint in which there was so much depth or intensity, with so little of that glare which becomes offensively obtrusive. The colors, too, are absolutely new; they are neither the rose, the violet, the peach, nor the blossom in which our mothers prided, but they are those with something superadded. The dyed surface has a power peculiarly its own, of separating two or more rays from the source of all color, light, and of sending them off in a most harmonious combi

nation.

The Mauve and Magenta are permanent colors. Light does not bleach them; the weaker acids do not stain them; the color is dependent on the oxidation of the base of it; whereas, in nearly all other colors, the action of oxygen is to destroy the color.

CANADIAN TIMBER FOR FRANCE.

A contributor to the January number of the "Annales Forestieres et Metallurgiques," a Parisian magazine of a semi-official character, writing under the heading of "Les bois de Canada," speaks of the decline of the timber exports of Norway, and of the impossibility of obtaining from thence the wood necessary for manufactures in France, and says:

"Everybody knows that our former colony is, so to say, a vast forest of four thousand leagues square, possessing as means of transit magnificent lakes and rivers, and in which whole armies of wood-cutters, or lumber

ers,' as they are called, cut down every year from eight to ten millions of cubic metres of timber, the greatest part of which is exported to the United States, and more particularly to England."

He goes on to argue in favor of exchanging for Canadian lumber the staple products of France, her wines, her porcelain, her silks, woollens and cottons, and above all, her " tabacde-eaporul," which, he remarks, is "the delight of French Canadians."

THE TELEGRAPH IN PERSIA.

In a late number of a Persian newspaper called the Vekaya we have an account of the opening of a telegraph line (MORSE's) between Teheran, the capital of Persia, and Tabreez, on or near the Urumia lake, four hundred miles distant. It follows the route of caravans. The inauguration came off on the 21st of January last, on the esplanade of the imperial palace, in the presence of the young sovereign, NACIR EDDine, all the dignitaries of the court and thousands of spectators. Questions were sent to Tabreez, and, when answered, the replies were repeated aloud amidst the joyous cries of the people and salvos of artillery. News that required twelve days ordinarily for transmission now came in a few minutes, much to the astonishment of the enthusiastic and wonderloving Persians. This miracle has been brought about by the Minister of Public Instruction, who is the uncle of the Shah, and by the director of telegraphs, ALI-KOULI-VEKAN, both of whom were publicly honored on the spot with princely robes, India shawls, daggers ornamented with diamonds and the cordon of the lion. We presume our friend MORSE I will in due time receive his share of the honors from NACIR EDDINE SHAH.

BASSWOOD.

In the United States, basswood is used to a considerable extent for seats of chairs, insides of drawers, parts of fanning-mills, and many other uses for which it is better adapted than almost any other wood. It is both light and strong, works easily and is not apt to split.

Basswood is one of the most abundant woods in Canada, but it has so far received little or no attention in commerce. The Quebec Advertiser urges that efforts be made to promote the export of basswood lumber, and also the manufacture for export of wooden-ware made from basswood.

In England a great business is carried on in the manufacture of whitewood ware, or Tunbridge-ware, and for such purposes, any wood which will "dry white" is used-the principal kinds being "chestnut”-i. e., horse-chestnut, a very different wood from the common chestnut, (castanea vesca)—and lime, or, as we call it, basswood. Referring to this, our Quebec contemporary considers that a good business might be done in exporting this wood to England.

For use in wooden-ware this wood must not be exported in logs, as in that state it can only be employed for the upper timbers of houses, ships, etc. But it must be exported in the shape of boards, inch, half-inch,

and even as thin as the eighth of an inch, for veneering. The great object is to get the wood to dry white, and to secure this, it must be sawn quite fresh, and before the sap has had time to ferment, and thus discolor the wood. The boards are taken from the saw-mill or pit as fast as they can be cut, hung up under shelter from the rain, in an open shed, with a free draught of air, (not in piles,) until so thoroughly dry that there is not the least probability of their becoming mildewed. There would be still more profit to the Canadians if they themselves should convert their basswood into articles of wooden-ware, with which Canada probably could supply the world.

FRENCH SCHOOL OF ART.

The French Central School of Arts and Manufactures is a remarkable one, and deserves a notice at length. It is under the direction and patronage of the State, and requires three years attendance from each pupil. The conditions under which a youth is admitted are strict enough, and occupy four columns of the Moniteur. We imagine there is not a professor in the best of our colleges who could pass the requisite examination to enter this school, so extensive, minute and difficult is the programme. None but a most skillful algebraist, geometrician, (descriptive, analytic, &c.,) architect, mathematician, draughtsman, physiologist, physician, chemist, anatomist, understanding all the divisions of each branch of these sciences, (more than four hundred in number,) must write on these various subjects, and also be examined orally to the satisfaction of the examiners. The whole expense of tuition is seven hundred and seventy-five francs per annum, and foreigners as well as natives are admissible. The questions in chemistry alone would puzzle our best instructors, and as to physiology, we think a good many clever men would find it difficult to explain clearly and promptly the questions. Division of functions, absorption and exhalation, digestive apparatus, the chemistry and mechanism of digestion; apparatus of circulation, its mechanism; the lymphatics, the respiratory apparatus, its mechanism and chemistry, its phenomena, animal heat, (the theory of this not yet settled,) structure and functions of the principal glands, structure and functions of the nervous system, structure and functions of the organs of sense, the vocal apparatus, osteology, structure and chemical composition of the bones, their articulation; the skeleton, the muscular system, structure and functions; classification of the animal kingdom, divisions, special characters of mammals, birds, reptiles, fishes, insects, annalides and acephala; botany, roots, branches, leaves, flowers and fruits, and elucidations of the natural method of JUSSIEN, are some of the divisions of one branch of inquiry. And yet young men as low in years as seventeen are expected to afford the greatest number of applicants for admission to this very school. This subject is suggestive-very.-N. Y. Evening Post.

CHAMBERS OF COMMERCE AND BOARDS OF TRADE.

Monthly Meeting of the Chamber of Commerce of New-York, Thursday, August 1st, 1861.

THE regular monthly meeting was held Thursday, PELATIAH PERIT, Esq., President, in the chair.

Mr. JOHN EWEN, President of the Pennsylvania Coal Company, and Mr. ROBERT H. MCCURDY, of No. 45 Park Place, were elected members of the Chamber.

In the absence of Mr. OPDYKE, Chairman of the committee appointed to wait upon Congress with the memorial passed at previous meeting, Capt. MARSHALL stated that he had a conversation with the Secretary of War, who said he had already sent his engineers to New-York to ascertain what was necessary to be done.

Ocean Mail Steamers.-Mr. DAVID OGDEN moved that the President be authorized to sign the following memorial:

To the Hon. MONTGOMERY BLAIR, Postmaster-General of the United States:

The undersigned, members of the Chamber of Commerce of the city of NewYork, respectfully represent that it is highly for the interest of the commercial community of this city that the mails from this country to Europe be transmitted by the steamers of the Ocean Steamship Company, which make their passage in the shortest time and with the greatest certainty. They therefore respectfully request that the Postmaster-General of the United States will cause such mails to be transmitted by the steamers of whichever company is able to make the most expeditious as well as reliable mail service.

Mr. A. A. Low objected to the Chamber committing itself upon this subject, as the course suggested might prove very detrimental to our own steamers. It was by large subsidies from the British government that the CUNARD line was enabled to keep up the fastest ocean steamers, and it was their boast that they had driven off our steamers by such means. It was notorious that the fastest vessels could be run only by aid of government patronage. The effect of this resolution would be to throw the whole mail service into the hands of the British steamers, and to take off entirely American steamers, of which we had but very few, and they not well sustained.

On motion of Capt. MARSHALL, the memorial was laid on the table, to be taken up at a future day.

Revenue and Internal Tax Bills.-Mr. A. A. Low offered the following:

Whereas, The government of the United States is engaged in a contest for the suppression of rebellion and for the maintenance of the integrity of the Union, which is destined to make a large demand upon the pecuniary resources of the country, and the demand must chiefly be met by means of repeated loans :

Resolved, That in the judgment of this Chamber, the success of the proposed loans will depend upon the enactment by Congress now in session, of revenue and internal tax bills adapted to the existing emergency, or that of the government; or that if the government should succeed in procuring money without making wise provision for the reimbursement of principal and interest, it will be upon terms discreditable to the national name and prejudicial to the national interest.

It was in view of the reluctance of many members of the Senate to pass the tax-bill now before them that he (Mr. Low) offered his resolution. There seemed to be a much greater willingness to spend the public money than to be taxed for its repayment, and he hoped that this expression of opinion, going from the Chamber of Commerce, would stimulate Congress to pass a bill that would establish the national credit. Mr. R. LATHERS approved of the motion, and wished to amend by appointing a committee of five to present the resolution, and aid Congress in the supervision of any bills before them for revenue and internal tax. In the hurry of legislation he feared that a great many crudities would be incorporated in the measures now before Congress. It was proposed to impose an income tax-a measure never resorted to, even in Europe, except as a last resort. He considered that that bill, as reported, would work a great injustice to the mercantile community, and to those who depended upon their salaries for a support, while (as evidently was intended) it would free the western lands and property generally in the interior.

Mr. ROYAL PHELPS doubted the policy of sending committees to Congress, except on important subjects, and such as were intimately connected with the business of the Chamber. When too frequently sent, they lost their force and were not well received.

Mr. Low thought that if the Chamber could not give a free expression of opinion on subjects so important to commercial interests it had better disband. The Chamber of Commerce, representing the commercial community, should say to Congress that if they wanted an extraordinary amount of money, there must be some measure passed that looked to payment, and thus support conservative action on the part of the govern

ment.

Mr. JONATHAN STURGES hoped the resolution would pass for the purpose of encouraging Congress to enact the tax bill.

Mr. S. DE WITT BLOODGOOD said this was an eventful moment in our history, and we should live or die by our valor and money. With all respect for the gentlemen composing the government, he did not think they were more learned or careful than men not in the administration; nor did he think the exertions of the Chamber of Commerce would fall to the ground. He had studied its history, and always found that the merchants of New-York had been foremost in support of every project for the glory and interest of the country. Whether received well by politicians at Washington or not, New-York was the bank from which the money must come, and why should not those who were ready to sacrifice lives and fortunes be heard? He thought that the merchants ought to express themselves freely.

The amendment by Mr. LATHERS was lost, and the resolution by Mr. Low was carried.

Mr. C. H. MARSHALL moved the following amendment:

Resolved, That, in the opinion of this Chamber, the tariff bill now under consideration of Congress should be framed so as to produce revenue only, and without regard to protection.

He thought that on many articles the duty was so great as to amount to a prohibition. Certainly such a tariff would diminish instead of increasing the revenue.

Mr. SAMUEL HOTALING opposed the resolution, stating that the great