Together on the navigation bridge, we are discussing the shipment. ". . . It is the exchange, Captain," he says. "The exchange is against us. These huge war purchases in the States cannot be balanced by the moderate exports we are able to send over. When we left Liverpool the sovereign was worth four dollars, seventy-one cents in America. I don't know where it is going to end. We can't make securities. There must be a lim----" Drumming of the wireless telephone cuts in on his words. "Operator wishes to know if he can leave the 'phones, sir? Says he has to see you." The bridge messenger turns aside inquiringly, holding out the receiver of the telephone as a context to his words. The request, that would have aroused an instant disquiet six days ago, now appears trivial and normal. There may be receipts to be signed. Approaching port the operator will be completing his accounts. We are unconcerned and resume our conversation until he arrives. He is insistent that it cannot be due to atmospherics. "A queer business, sir. Thought it best to report instead of telephoning. Some station addressing a message to ABMV [all British merchant vessels], and another trying to jam it out. Can't get more than the prefix, when jamming begins. No, not atmospherics. I've taken ABMV, though distant, twice in this watch, and, looking up the junior's jottings for the last watch, I see he had traces. Whatever is jamming the message out is closer to us than the sender. I dunno what to make of it!" "You mean that a message from a land station to us is being interfered with, deliberately, from somewhere near at hand?" He produces the slip of his junior's scribbles. Among the jumble of noughts and crosses, there is certainly a hastily scrawled ABMV, then x's and x's. "What else, sir? At first I thought it was atmospherics--x's were fierce last watch--but x's can't happen that way twice running!" "All right! Carry on again. Let me know at once if anything further. Gear to be manned continuously from now on. Keep your junior at hand." [Illustration: 'OUT-BOATS' IN A MERCHANTMAN]