Tin and Copper Prices—The metal trade of Birmingham, England, rules the world in respect to articles of tin, copper, and light jewelry. Since we last noticed the rise in the price of tin, another advance has taken place of no less than $10 per ton. The price of copper has also advanced to no less than $695 per ton; the small manufacturers of copper and brass articles, in Birmingham, have stopped manufacturing, owing to the higr price of tin and copper. INCRUSTATIONS IN BOILERS—Fredk. Dam a chemist, of Brussels, Belgium, has lately taken out a .patent for employing a solution o soda, in steam boilers, for the purpose of precipitating impurities in the water. Soda wil precipitate lime, which will fall to the bot? torn. Some of the salts of soda are dissolvec - in hot water and then poured into the boiler This substance is not expensive and can easi. Iy be tested. In our opinion it will be fount , to work very well. IMPROVEMENT IN THE MANUFACTURE oi i IRON—This is a subject of deep interest to ou manufacturers, and a discovery has recently I been made in England, which is of the utmos ' consequence to all engaged in that art whi ? use coke for smelting. As we leain by ou I cotemporary, the " London Mechanic's Maga ? zine," at a late meeting ef the Institution o Civil Engineers, a paper was read by W Fairbairn, C. E., on the increased strength e ? cast-iron produced by the use of improvei coke. It was stated that the quality ot cast t iron had greatly deteriorated by the applica - tion ot the Hot Blast, by which a large pe ? centage of slag and other impurities, viz., sul - phur, phosphorus, c, were reduced into cas and malleable iron, destroying its tenacity - and making it red and cold short. Impure fue is also a great cause of destroying the tenaci - ty of cast-iron, especially when it contain I sulphur. The improvement has been madi - in removing the sulphur from the coal, [roi - that was melted with common coke containei s 0281 proportions of sulphur ; some kind o " iron, melted with purified coke, contained onl; I 0-191 proportions of sulphur. A great in b crease of strength had been obtained in thi - improved iron. The coke was purified b; t adding a considerable quantity, in layers, o a common salt, among the coals. This salt act s upon the sulphur in the coal, when subjectei - to heat in the coke-oven, forming the chlorid - of sulphur and disengaging it. A portion o t the sulphuret of sodium was left, but this ii - the iron -furnaces does not yield its sulphui f but passes off, during combustion, into th 3 cinders. 3 Another plan for using the salt so as to re e move sulphur in the coal while in the smelt : ing furnace, is to add a considerable quantity -* "of the salt (chloride of sodium) with the or s so as to mix it with the coal and the iron.This is a good plan for those ironworks, which employ coal and not coke in smeltiDg. We are not informed ot the exact quantity of salt used, and in fact this could not be determined, as that must be according to the quality of the coal and ore. Our manufacturers can easily try the experiment with half a bushel of salt to the ton. In some experiments made with iron produced without the salt and with it, on bars one inch square ; that made with improved coke was found to be from 10 to 20 per cent, stronger. The cast-iron made with improved coke was superior in the ratio of 5 to 4. In England nothing but coke is used as fuel for locomotives ; it will yet be employed extensively in our country, as we have bituminous coal fields of greater extent than all those known in the world beside; our anthracite fields are mere plots in comparison with our bituminous fields. Coke made with salt, by removing the sulphur, must be excellent for locomotives ; and will tend to make the tubes endure twice as long. We commend this subject to all those engaged in making coke and manufacturing iron.