While constructing this line, Zola, in June, 1823, obtained personally the imperial authorisation to make another one, connecting Linz with Gmunden and the Salzkammergut--the so-called "Austrian Switzerland," industrially important for its extensive salt-works. But he became disappointed with the financial results of the Budweis line, and, accordingly, in September, 1830, he sold the Gmunden concession. It seems likely that he had then already quitted Austria. There are indications that he may have visited England with Ritter von Gerstner, and have sojourned for a time in Holland; but before the end of 1830 he was certainly in France, writing to King Louis Philippe respecting a scheme he had devised for the fortification of Paris. In the spring of 1831 he was in communication with the French War Office on this same subject, whilst also soliciting an appointment in the Foreign Legion, in Algeria, with the rank of captain.[7] The fortification scheme was shelved, but the appointment was granted, excepting in one respect: it was as a lieutenant, not as a captain, that François Zola entered the Foreign Legion in July, 1831. His career in that corps proved very brief, and ended strangely. Many years afterwards an unprincipled journalist, anxious to discredit Émile Zola's championship of Captain Dreyfus, raked up the episode in order to denounce the novelist as the son of a thief. But it is certain that some documents cited at the time were entirely forged, that others were falsified in part, and that others, again, were suppressed. This can occasion no surprise when it is remembered that one of the _dossiers_ concerning François Zola, preserved at the French War Office, passed for a time into the possession of the notorious forger, Colonel Henry;[8] and that an unscrupulous Minister, General Billot, by asserting authoritatively that certain papers did not exist,[9] contrived to delay their discovery. Those matters will require notice hereafter; at this stage one need only mention that the attack on François Zola's memory was answered first in a work called "Le Père d'Émile Zola" by a Socialist journalist, writing under the name of "Jacques Dhur," and secondly by Émile Zola himself in a series of newspaper articles, which he reprinted in a volume entitled "La Vérité en Marche."