Mr. Henson has also succeeded in establishing a traffic in gunpowder, by inventing a carriage of sheet iron, lined with wood, in which four-and-a-half tons of gunpowder can be conveyed without fear of explosion either from concussion or external combustion. The shops at Camden have room for building or repairing 100 waggons. They are to be seen in every stage of progress. The great object is to combine strength with lightness. If the strength being the same, the saving of a ton can be effected in a waggon, it will amount to from thirty to ninety tons in an ordinary goods train. An important consideration, for deadweight is the great enemy of the railway, and ninety tons of useless weight is equivalent to a loss of 90 pounds in sending a goods train a journey to Birmingham. British oak is the favourite wood for the frames of railway waggons; teak, if of equal quality, is dearer, and the inferior is heavier, without being so strong. If in any of the many countries with which we trade a wood can be discovered as good and as cheap as English oak, the railways which are constantly extending their carrying stock, can afford a steady demand. About the passenger carriages, which every one can see and examine for himself, there is not much to be said. On the Continent, where they cannot afford to use mahogany, they use sheet-iron and papier-machee for the panels; in England, mahogany chiefly in the first class. When we began, stage coaches were imitated; there are some of the old cramped style still to be seen on the Richmond line; then came enormous cages--pleasant in summer, fearfully cold in winter, without fires, which have not been introduced in England, although they are found in the north of Europe and America. A medium size has now come into favour, of which some fine specimens are to be seen in the Hyde Park Exhibition. On the Great Northern line some second-class carriages have been introduced, varnished, without paint, and very well they look. Economy again, and the increase of branches, have led to the use of composite carriages for first and second-class passengers all on one body. These, which were in use years ago on the northern coal lines, are now revived and improved. The Camden station has received an entirely new feature by the completion of the line to the docks and to Fenchurch Street, with stations at Islington, Hackney, and Bow. Already an immense omnibus traffic has been obtained--a sort of traffic which produces the same effect on engines as on horses. They are worn out rapidly by the continual stoppages. But horses show wear and tear directly, whereas iron and brass cannot speak except through increased expenses and diminished dividends.