Prior to the war period, between the years 1910 and 1914, a German undertaking called the Deutsche Luftfahrt Actien Gesellschaft conducted a commercial Zeppelin service in which four airships known as the Sachsan, Hansa, Victoria Louise, and Schwaben were used. During the four years of its work, the company carried over 17,000 passengers, and over 100,000 miles were flown without incurring one fatality and with only minor and unavoidable accidents to the vessels composing the service. Although a number of English notabilities made voyages in these airships, the success of this only experiment in commercial aerostation seems to have been forgotten since the war. There was beyond doubt a military aim in this apparently peaceful use of Zeppelin airships; it is past question now that all Germany’s mechanical development in respect of land, sea, and air transport in the years immediately preceding the war, was accomplished with the ulterior aim of military conquest, but, at the same time, the running of this service afforded proof of the possibility of establishing a dirigible service for peaceful ends, and afforded proof too, of the value of the dirigible as a vessel of purely commercial utility. [Illustration: The ‘Bodensee’ German passenger balloon.] In considering the possibility of a commercial dirigible service, it is necessary always to bear in mind the disadvantages of first cost and upkeep as compared with the aeroplane. The building of a modern rigid is an exceedingly costly undertaking, and the provision of an efficient supply of hydrogen gas to keep its compartments filled is a very large item in upkeep of which the heavier-than-air machine goes free. Yet the future of commercial aeronautics so far would seem to lie with the dirigible where very long voyages are in question. No matter how the aeroplane may be improved, the possibility of engine failure always remains as a danger for work over water. In seaplane or flying boat form, the danger is still present in a rough sea, though in the American Transatlantic flight, N.C.3, taxi-ing 300 miles to the Azores after having fallen to the water, proved that this danger is not so acute as is generally assumed. Yet the multiple-engined rigid, as R.34 showed on her return voyage, may have part of her power plant put out of action altogether and still complete her voyage very successfully, which, in the case of mail carrying and services run strictly to time, gives her an enormous advantage over the heavier-than-air machine.