When he had returned to Cape Tariff, after parting with the Dipsey, he had received several messages from Sammy, which assured him that the submarine voyage was proceeding satisfactorily. But when he went on board the Go Lightly and started homeward, he would be able to hear nothing more from the submarine voyagers until he reached St. John's, Newfoundland--the first place at which his vessel would touch. Of course constant communication with Sardis would be kept up, but this communication might be the source of great danger to the plans of Roland Clewe. Whatever messages of importance came from the depths of the arctic regions he wished to come only to him or to Mrs. Raleigh. He had contrived a telegraphic cipher, known only to Mrs. Raleigh, Sammy, and two officers of the Dipsey, and, to insure secrecy, Sammy had been strictly enjoined to send no information in any other way than in this cipher. For years there had been men, both in America and in Europe, who had been watching with jealous scrutiny the inventions and researches of Roland Clewe, and he well understood that if they should discover his processes and plans before they were brought to successful completion he must expect to be robbed of many of the results of his labors. The first news that came to him on his recent return to America had been the tale told by Sammy Block, of the man in the air who had been endeavoring to peer down into his lens-house, and he had heard of other attempts of this kind. Therefore it was that the telegraphic instrument on the Dipsey had been given into the sole charge of Samuel Block, who had become a very capable operator, and who could be relied upon to send no news over his wire which could give serviceable information to the operators along the line from Cape Tariff to Sardis, New Jersey. But Clewe did not in the least desire that Margaret Raleigh should be kept waiting until he came back from the arctic regions for news from the expedition, which she as well as himself had sent out into the unknown North. Consequently Samuel Block had been told that he might communicate with Mrs. Raleigh as soon and as often as he pleased, remembering always to be careful never to send any word which might reveal anything to the detriment of his employers. When a message should be received on board the Dipsey that Mr. Clewe was ready to communicate with her, frequent reports were expected from the Master Electrician, but it would be Sammy who would unlock the cover which had been placed over the instrument. Before he retired to his bunk on the first night on board the Dipsey, Sammy thought it proper to send a message to Mrs. Raleigh. He had not telegraphed before because he knew that Mr. Clewe would communicate fully before he left Cape Tariff.