My father died in 1892 and we had not at the time of his death learned of Popoff's microphone-coherer in which steel filings were mixed with carbon granules. The magnetic waves received at first by us presumably from Mars, and later, as the communications indisputably show, from that planet, were taken upon a Marconi receiver, or what was practically that. My father became more and more interested in the direction of interplanetary research by means of the magnetic wave. He argued vehemently, buoyed up by his increasingly augmented hopes as our own experiments improved, that the electric wave through space moving in an ethereal fluid of the extremest purity would progress more rapidly than in our atmosphere, that the tension of such waves would be greater, that they could be so "heaped up" as he expressed it--(_In the Slaby-Arco system an apparatus is employed consisting of a Ruhmkorff coil with a centrifugal mercury interrupter, by which a steeper wave front of the disruptive discharge is secured_.--Editor)--that their reception over the almost impassable distances of space would be made possible. This idea of piling up the waves was suggested by purely physical analogies. The enormous waves generated by severe storms upon the ocean travel farther than the smaller waves, and are less consecutively dissipated by the resistance of the water, the traction of its molecules and the occasional diversion of cross disturbances from other centers. Again some experiments made invacuo upon a limited scale seemed to show the accuracy of his predictions. Through a glass tube one foot in diameter and ten feet long we sent magnetic waves both when the tube was filled with air and when it was exhausted. Our means of measuring the time required in both cases were quite inadequate--perhaps there was no appreciable difference--but the records in the latter case, secured upon a Morse register, were unmistakably more vigorous and audible. At last our various results had reached a point where we felt justified in extending the limits of our investigations. We had up to this time only tried our messages between the two stations upon the plateau of Mt. Cook. My father now proposed that I go to Christ Church, install a sender (transmitter) and send messages to him at the observatory. I did so and the experiment was convincing. The day before I was ready to transmit a message I had attended an attractive church service--it was toward the close of Lent in the year 1889--and as my father was entirely unprepared for the account I proposed to give him of the function, I thought its correct transmission would afford an indubitable proof of our success. I wrote out the description. It was received by my father with only ten imperfect interpretations in a list of 1,000 words.