"No, the Fenachrone are far ahead of us in that subject, because of their observatories out in open space and because of their gigantic reflectors, which cannot be used through any atmosphere. We are further hampered in having darkness for only a few hours at a time and only in the winter, when our planet is outside the orbit of our sun around the great central sun of our entire system. However, with the Rovolon you have brought us, we shall have real observatories far out in space; and for that I personally will be indebted to you more than I can ever express. As for the chart, I hope to have the pleasure of examining it while you are conferring with Rovol of Rays." "How many families are working on rays--just one?" "One upon each kind of ray. That is, each of the ray families knows a great deal about all kinds of vibrations of the ether, but is specializing upon one narrow field. Take, for instance, the rays you are most interested in; those able to penetrate a zone of force. From my own very slight and general knowledge I know that it would of necessity be a ray of the fifth order. These rays are very new--they have been under investigation only a few hundred years--and the Rovol is the only student who would be at all well informed upon them. Shall I explain the orders of rays more fully than I did by means of the educator?" "Please. You assumed that we knew more than we do, so a little explanation would help." "All ordinary vibrations--that is, all molecular and material ones, such as light, heat, electricity, radio, and the like--were arbitrarily called waves of the first order; in order to distinguish them from waves of the second order, which are given off by particles of the second order, which you know as protons and electrons, in their combination to form atoms. Your scientist Millikan discovered these rays for you, and in your language they are known as Millikan, or Cosmic, rays. * * * * * "Some time later, when sub-electrons were identified the rays given off by their combination into electrons, or by the disruption of electrons, were called rays of the third order. These rays are most interesting and most useful; in fact, they do all our mechanical work. They as a class are called protelectricity, and bear the same relation to ordinary electricity that electricity does to torque--both are pure energy, and they are inter-convertible. Unlike electricity, however, it may be converted into many different forms by fields of force, in a way comparable to that in which white light is resolved into colors by a prism--or rather, more like the way alternating current is changed to direct current by a motor-generator set, with attendant changes in properties. There is a complete spectrum of more than five hundred factors, each as different from the others as red is different from green.