The Emperor and Empress of Russia, on Wednesday, May 27. 1885, the second anniversary of their coronation at Moscow, opened the Maritime Canal, in the Bay of Cronstadt, the shallow upper extremity of the Gulf of Finland, by which great work the city of St. Petersburg is made a seaport as much as London. St. Petersburg, indeed, stands almost on the sea shore, at the very mouth of the Neva, though behind several low islands which crowd the head of the Gulf; and though this is an inland sea without saltness or tides, it is closed by ice in winter. Seventeen miles to the west is the island of Cronstadt, a great fortress, with naval dockyards and arsenals for the imperial fleet, and with a spacious harbor for ships of commerce. The navigable entrance channel up the Bay of Cronstadt to the mouth of the Neva lies under the south side of Cronstadt, and is commanded by its batteries. As the bay eastward has a depth not exceeding 12 ft., and the depth of the Neva at its bar is but 9 ft., all large vessels have been obliged hitherto to discharge their cargoes at Cronstadt, to be there transferred to lighters and barges which brought the goods up to the capital. "The delay and expense of this process," says Mr. William Simpson, our special artist, "will be understood by stating that a cargo might be brought from England by a steamer in a week, but it would take three weeks at least to transport the same cargo from Cronstadt to St. Petersburg. Of course, much of this time was lost by custom house formalities. Sometimes it has taken even longer than is here stated, which made the delivery of goods at St. Petersburg a matter of great uncertainty, thus rendering time contracts almost an impossibility. This state of things had continued from the time of Peter the Great, and his great scheme had never been fully realized. The increase of commerce and shipping had long made this a crying evil; but even with all these difficulties, the trade here has been rapidly growing. A scheme to bring the shipping direct to the capital had thus become almost a necessity. As Manchester wishes to bring the ocean traffic to her doors without the intervention of Liverpool, so St. Petersburg desired to have its steamers sailing up to the city, delivering and loading their cargoes direct at the stores and warehouses in her streets. If Glasgow had not improved the Clyde, and had up to the present day to bring up all goods carried by her ocean going steamers from Port Glasgow--a place constructed for that purpose last century, and which is twenty miles from Glasgow--she would have been handicapped exactly as St. Petersburg has been till now in the commercial race.