I. On a fourth state of matter, in a letter to the Secretary. By W. Crookes, F. R. S

Abstract

Dear Professor Stokes, In introducing the discussion on Mr. Spottiswoode and Mr. Moulton’s paper on the “ Sensitive State of Vacuum Discharges,” at the meeting of the Royal Society on April 15th, Dr. De la Rue, who occupied the chair, good-naturedly challenged me to substantiate my statement that there is such a thing as a fourth or ultra-gaseous state of matter. I had no time then to enter fully into the subject; nor was I prepared, on the spur of the moment, to marshal all the facts and reasons which have led me to this conclusion. But as I find that many other scientific men besides Dr. De la Rue are in doubt as to whether matter has been show to exist in a state beyond that of gas, I will now endeavour to substantiate my position.