As to the project of attracting the attention of the Martians to the fact that there are rational beings on the earth, it seems to me that if there are any who insist upon making us conspicuous in this way it would be better to devise some simpler way than the construction of a mirror several miles in diameter. A large black spot on the white alkali plains could be constructed at much less expense, and would be as easily perceived by the Martians, if they exist and have telescopes as powerful as ours. It would be as easy to “wink” signals with the black spot as with a mirror of equal size, probably easier.
The spot could be made in small sections of black cloth arranged to roll up on long cylinders, exposing the white ground underneath, the cylinders being operated simultaneously by electric motors. I am unable to say how much four square miles of cloth would cost. You will have to consult the dry goods houses or the people who write arithmetic.
We should probably get an answer, for the Martians are supposedly older and wiser than we are.
I have never, and am not now, giving any attention at all to the problem of signaling to Mars.
I don’t think we need go any further to justify my adjective “sensational”. Nor need we blame Professor Wood for the sensationalism. He has perpetrated some gigantic and Gargantuan hoaxes — as hoaxes — but is of a rigid, almost ultraconservative integrity in the field of serious science. He had never sanctioned any of the fantastic and gratuitous predictions. Indeed, he had never claimed anything for the mercury telescope. He had merely invented it, and there it was…
As for my second adjective, “useless”… well, the mercury telescope isn’t there, or anywhere, any more. When the moon rises over the cowshed, no mirror flashes, no Katie waits, and no quicksilver gleams. It has gone the way of the heifer calf. It just didn’t work out pragmatically. One thing I wondered about, and which may have had something to do with its demise, was how the hell you could point a hole in the ground at the particular planet, star, or galaxy you wanted to study at the time? Wood says my wonder is justified, and that later he mounted over the pit a twenty-inch plane mirror of silvered glass and was able to view objects which were widely removed from the zenith. I doubt if it could have helped much.
Now to justify our third adjective, as to its being one of the most “significant” things Wood ever did. The method of driving the mirror with an independent circular rotor he subsequently applied to all of the dividing engines used for ruling diffraction gratings, and at once got rid of certain errors in the proper spacing of the lines. It has since become a standard engineering practice. So, despite its immediate uselessness, the whole thing was of an instructive significance, as an example of how your pure scientist sets himself a problem — which may or may not lead to practical results — and solves the problem by breaking it into its component parts and dealing separately with each. Wood’s own technical description (written at the time and preserved in his scientific papers) of the problem, its motivations and the technique employed in solving it, is a clear, modest, and illuminating exposition of how the wheels go round — in the making of a mercury telescope and also in the scientific brain.
Before it went into limbo, the mercury dish mirrored one profound reflection, not of starlight but of rural American philosophy. It was during the Bryan-Taft campaign, and an old East Hampton farmer, after staring at the myriad stars reflected in the mercury telescope, sighed and said,
“Well, I don’t know as it makes so much difference after all whether Taft or Bryan’s elected..”.
The old farmer’s reflection was profound, but was it original? Or have people been saying it since the time of Pythagoras?
Now while the mercury telescope was following the heifer calf into oblivion, Wood was already engaged in the construction — in this same unique barn-cowshed-laboratory at East Hampton — of a gigantic spectroscope, or rather spectroscopic camera, which was destined to become an entirely different kettle of cats. It was, and for years continued to be, the largest and best instrument of its sort in the world, and in addition to making the Woods’ house cat as immortal as the parrot of Archimedes, it marked an epochal advance in spectral knowledge and analysis. One of the many things it did was to resolve for the first time the complicated spectrum of iodine, which has some forty thousand lines. But whenever this is mentioned by scientists and physicists, whether here or in Tokyo or Singapore, somebody always interrupts to tell the story of the cat, so I think I’d better follow custom and dispose of the Wood pussy. There are many versions of the story. It was twisted by Time a couple of years ago, and became a sort of feline Rin-Tin-Tin animal serial in the hands of the newspaper feature writers, who turned the cat into a permanent magician’s assistant and had it regularly doing its stunt whenever Wood called, “Pussy, pussy, come and clean the cobwebs”. It had, indeed, so many variants that I’m not sure Wood himself is any longer able to give a trustworthy account, and the cat cannot be interviewed because she’s dead. Yet what apparently actually happened is simple and easily told. The spectroscope had a long wooden tube, forty-two feet in length and six inches or so in diameter, projecting out through the side of the barn, to an iron post in the cowyard, fitted at one end with a diffraction grating and at the other with a slit and a mirror. During the first winter and spring after its construction, the spiders got in and wove their webs. When Wood came down in June he spied the arachnean invasion. He grabbed the family cat and stuck it — not without a struggle — into one end of the tube, which he then closed up. Pussy, having no alternative, squirmed her way through the tunnel towards the daylight and bounded out at the other end trailing a bridal veil of spiderwebs over the fence and across the lawn. It hadn’t occurred to the Professor that it would be long remembered, though he casually mentioned the episode in a technical paper in the Philosophical Magazine. It was just a quick, efficient, costless way of obtaining a desired result with whatever came nearest to hand.
This spectroscopic camera was a marvel of scientific — and practical — ingenuity. Friends, fellow-scientists, curiosity-seekers, and journalists again flocked to the now world-famous barn. There are many clippings, some highly technical, which describe what was going on there in 1912. The picture which comes clearest to me is the description which appeared in the Brooklyn Daily Eagle of Sunday, September 1, 1912, in which the writer said:
One passing along the road would never suspect that the place was other than a quaint building housing farm animals until the professor swings open the huge doors and shows you the interior.
The new spectroscope, which the professor built entirely himself, is essentially so simple a mechanism that one would hardly expect any startling results could be obtained from it. It consists of a long wooden tunnel, forty-two feet in length and seven inches square, terminating at one end in an achromatic lens, six inches in diameter, having a forty-two-foot focus, just the length of the tunnel. Beyond the lens, at the same end, is the diffracting grating which decomposes the light into the prismatic colors. This grating is a piece of polished metal ruled with diamond scratches, 15,000 to the inch, making a total of 75,000 vertical lines on the whole surface, which is five inches square.
The grating rotates on a vertical axis, turned by a rod and gearing wheel, so that the professor may use any part of the spectrum he wishes at a time. The instrument is so powerful that only a small part can be used at a time. The lines on the polished plate act just the same as a prism in diffracting or decomposing the light into the prismatic colors, but make the instrument much more powerful than an ordinary prism.