To accomplish the purposes they had in mind, the Navy Department engaged the services of all available machinery welders and patchers, many of whom were voluntarily offered by the great railroad companies. Most of the time that was required was due not so much to actual repair work as to the devious and tedious task of dismantling all machinery from bow to stern of every ship in order to make certain that every bit of damage was discovered and repaired. In this way all chance of overlooking some act of concealed mutilation was obviated. [Illustration: _From a photograph copyright by International Film Service._ REPAIRING A DAMAGED CYLINDER OF A GERMAN SHIP FOR FEDERAL SERVICE.] It would appear that explosives were not used in the process of demolition by the Germans, but at the time the engineers could not be sure of this, and as a consequence as they worked they were conscious of the danger of hidden charges which might become operative when the machinery was put to the test, or even while the work of dismantling and inspection was being carried on. There were, however, discovered, as a result of this rigid investigation of every mechanical detail, many artful cases of pipe-plugging, of steel nuts and bolts concealed in delicate mechanical parts, of ground glass in oil-pipes and bearings, of indicators that were so adjusted as to give inaccurate readings, of fire-extinguishers filled with gasoline--in fact, the manifold deceits which the Germans practised would make a chapter of themselves. Suffice to say, that through painstaking investigation every trick was discovered and corrected. On each vessel there was no boiler that was not threaded through every pipe for evidence of plugging, no mechanism of any sort that was not completely dismantled, inspected, and reassembled. On one ship the engineers chanced to find a written record of the damage inflicted. In every other case the search for evidence of sabotage was blind. This memorandum in the case of the one ship was evidently left on board through an oversight, and written in German, was a veritable guide-book for our engineers. In order that the reader may have some idea of the sort of damage done, the following extracts from that memorandum of destructiveness is herewith presented: "Starboard and port high pressure cylinders with valve chest; upper exhaust outlet flange broken off. (Cannot be repaired.)" "Starboard and port second intermediate valve chest; steam inlet flange broken off, (Cannot be repaired.)" "First intermediate pressure starboard exhaust pipes of exhaust line to second intermediate pressure flange broken off. (Cannot be repaired.)" "Starboard and port low pressure exhaust pipe damaged. (Cannot be repaired.)"