The references to "undampt" waves used Hugo Gernsback's phonetic spelling for "undamped". And what were originally known as "undamped waves" are now generally known as "continuous waves", or "CW".
Radio Amateur News, December, 1919, page 260:

Developing  the  Radiophone
O NE of the most fruitful branches of development in the Radio Art, no doubt lies at present in the radio telephone. The R. T. is nearer to the heart of every radio amateur than any other single thing in wireless, and rightfully so.
    As I have often pointed out in the past, R. T. will be the amateur's salvation; it is the one great thing that will put American Radio Amateurism in a safe and respected position. The R. T. will lift the now--in many quarters despised--art into the great position it deserves.
    Up to now Radio has been more or less a plaything, a sport, a sort of diversion for young boys from sixteen to seventy years old. Due to the always present irresponsible element within our midst, radio has often fallen into disrepute, and for this reason new radio bills just now are thicker than flies in the summer. Already radio inspectors are issuing warnings to those amateurs who are again hogging the ether, just as before the war--see this issue for details. What then will happen to us three or five years from now when fifty thousand more of us insist in tapping the key. Simply this: Amateur Radio will be closed down tight by legislation. And there will be no comeback this time, either. If it happens, we will only have to thank ourselves for it. Now, I do not wish to appear as an alarmist, but you will grant that, having had to do more with radio amateurism and radio legislation, than perhaps anyone else in this country since 1904, I ought to see clear and know whereof I speak.
    As the situation now looks to me, our only salvation lies in the R. T. Once we get this firmly implanted into our minds we will have gone a long way towards the ultimate goal. I need not recite here all the advantages of the R. T. As far as the amateur is concerned--three are sufficient: First, no code need be learned or used; second, a radio phone message takes but a fraction of the time to send compared to a radio telegraph message; third, and most important, the R. T. does away with most of the now dreaded interference.
    We must therefore devote all our energies in developing the R. T. We must leave no stone untouched to secure results. We must experiment every day till the goal is achieved. And, in passing, the amateur who invents a workable, practical, R. T. outfit that works on six dry cells, will have a fabulous gold mine. Some of our big electric companies will pay a king's ransom for the patent, this very minute.
    Using the audion as a generator for undampt waves and as a R. T. transmitter is of course a great accomplishment in itself. And the device works well,--better than anything else, so far. But it is not the ultimate goal. Vacuum tubes of the audion type are tricky as yet, and not too practical. Unless you use special tubes--and you can't just now, due to a complicated patent situation--the speech is not always clear, and far from satisfactory. At the critical period, the tubes often "go bluey" and refuse to "talk."
    Amateurs therefore should look for substitutes of vacuum tubes, or devise other tubes, employing entirely different principles. The writer years ago, experimented with a sort of quenched gap, in a vacuum, also gaps enclosed in different gases. The results, however, were not too encouraging.
    Trials should be made with plate gaps in various solutions, and effects noted. As a test the microphone can be connected in series with the primary and battery of a spark coil, or transformer. Many vacuum tubes, not necessarily using the Edison effect, could be tried. Tubes with mercury vapor--affording a "sparkless" discharge across an enclosed gap, should be worth while experimenting with. Quenched gaps made of unusual and untried metals or other materials, might unearth unknown and surprising qualities. Has anyone ever tried a spark gap made with ceric iron--the stuff that is used to make cigar lighters?
    Then, if you do not wish to experiment with any of these, you can fall back upon the arc as a source of undampt waves. Perhaps you can find some materials other than carbon that give a satisfactory arc at a low voltage. Did you know that you can maintain a microscopic arc at about 8 volts with two carbons as thin as pencil-leads. I tried this stunt years ago and it works well. Now if you can impress the voice currents on such an arc and step up your voltage to about 10,000 in order to radiate from your aerial, you will have a fine radio telephone. It should not be impossible to do this.
    There are a thousand other fascinating stunts that you may try out. Each one may prove to be the "missing link."