The loss of the blue-prints did not hold up the progress of our friends in the least, as it was only the matter of fifteen or twenty minutes' work for Paul to make a new set from the tracings he had at home; but there were unexpected difficulties met here and there in the constructive work, as is always the case in large mechanical undertakings of an original nature, besides which the young builders ran into the usual delays caused by slow deliveries of parts and materials from distant dealers and manufacturers; and sometimes the railroads were tardy in transporting shipments.