So we first paid court to the lighter captains and their aids. We followed shipments of sugar from the refinery doors to the lighters, saw the shipping clerk hand over his bill to the captain, saw the lighter pull out for a pier somewhere about the harbor, followed him to the pier, and watched the transfer of the cargo into the vessel’s hold. If a lighterman knew that hand-sewn bags could be ripped open, and wished to insert a bomb and close the bag again, he would have to do it on the way from the refinery to the pier--of that we were confident, for as soon as the lighter pulled up to the vessel’s side the stevedores rushed the cargo into the hold, the hatches were sealed, and the cargo-checker, employed by the vessel, turned over to the lighter captain his receipt for the consignment. There was apparently no other time for tampering with the bags. How to watch the bags themselves from the refinery into the vessel was a troublesome problem. The river, during the daytime, is in constant traffic, and navigation for a cumbersome lighter in the river-paths is about as comfortable as crossing Fifth Avenue on foot at rush hour. The river at night was comparatively free, and it was then that most of the lightering was done. A waterman can identify the uncouth shapes of queer craft on dark waters, a landsman cannot, but we had to make the best of a bad bargain and chase the lighters in a motorboat, often diligently following a blinking light through the mist for hours to discover finally that it was on the wrong ship. Ships on a dark river are like timid spinsters in a dark street--they exhibit, perhaps through fear of collision, perhaps because ships are feminine, a strong suspicion of anything that approaches. Our barking motorboat advertised itself half a mile away. If we drifted we lost our quarry. We tried to smuggle men aboard the lighters, but there were so many, and they were bound in so many different directions, that we were not manned for this. So passed June and July. It was a thankless task, and one which had its risks. Detective Senff fell into the river one night when he was chasing a suspicious character around under a pier at the foot of West 44th Street and nearly drowned before he could be pulled out. The case seemed to be getting no further than abstractions. Ashore, however, we learned that most of the lighter captains in the harbor were Germans, and in an effort to reduce the field we learned the names of the captains of the lighters which had most frequently visited the vessels on which fires had occurred. This took time and an exhaustive study of lighterage receipts, but it brought out the fact that in every case of a delivery of sugar to an outward bound vessel, the captain of the lighter had returned a full receipt--which exploded the possibility that a lighterman might take a bag from one shipment, put a bomb in it, and add it to the next.