The innovations introduced by photography have revolutionized the processes of stellar measurement. Instead of the laborious task of measuring the stars through the telescope, the photographic plate can be studied at ease as a correct and identical chart of the heavens and the results thus obtained placed at the disposal of astronomers. My father appreciated this and amongst his numerous projects of scientific usefulness the preparation of photographs of the stars fully occupied his mind. We had no Meridian Circle, as it was less in the direction of the determination of the position of stars than in the elucidation of the surfaces of planets, that my father's astronomical predilections lay. Our telescope was a refractor and had an objective of two feet diameter. It was firmly supported on a trap rock pedestal. The eye piece adjustment was unusually successful, and the remarkable freedom of the objective from any traces of spherical or chromatic aberration gave us an image of surprising clearness. The photographic results were admirable. I imagine few more satisfactory photographs of the face of Moon have been made than those we secured, so far at least as definition is concerned, and the detail within the limits of our powers of magnification. The telescope was very slowly installed and it was well in 1885 before we were able to use it for either observation or photography. As the surprising messages detailed in the following pages came by means of wireless telegraphy, I will dwell for an instant for the benefit of the non-scientific reader, upon the investigations made by my father and myself in this subject. The installation of a wireless telegraphic station is not necessarily difficult. The progress made since my father and myself began these experiments has been, of course, considerable, and yet so far as I am able to ascertain the new devices in this direction were largely anticipated by us. The tuning of wireless messages by which the interception of messages is prevented was certainly forestalled by us, though in the communications with Mars herein detailed the ordinary [_non-syntonic_.--Editor] receiver was employed. We employed an induction coil, emitted a wave by a spark, and had a wire rod [_antenna_.--Editor] which was in turn part of an induction coil. This was the sender (transmitter) and we could regulate the wave length so that a receiving wire adjusted for such a wave could only receive it. [There seems to be implied in these words an arrangement known as the Slaby-Arco system, which American readers have had described for them by M.A. Frederick, Collins, Sci. Amer., March 9 and Dec. 28, 1901.--Editor.] The receiver consisted of iron filings in which later carbon particles were added.