PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 457 



light and actinism, are tlie products of the same highly attenuated imponder- 

 able fluid, moving in waves of difierent lengths. The eye is sensitive only 

 to the action of one octave of waves, and the impression of color depends on 

 the relation of the velocities of these waves with each other, that is, on the 

 ratio of vibrations. Thus, the apparent paradox of the lightest color, 

 yellow, and darkest, indigo, being within, rather than at the extreme of 

 the spectrum, is accounted for by harmonial relations alone. 



The longer waves of ether, or aeth waves, give the sensation of heat, 

 and the greater the amplitude of the wave the stronger is the heat force. 

 These longer waves may give rise to shorter waves by sympathetic action, 

 as a musical note of a given pitch excites other sounds called harmonica, 

 thereby setting in motion the waves of the middle octave, on which the 

 sensation of light depends. Thus we find that all ponderable bodies, at a 

 certain temperature, become luminous, 'i'hus, too, actinic effects are gen- 

 erated from heat; they commence in the blue ray, increase in force to the 

 violet, and extend beyond into the invisible rays of the spectrum. The 

 peculiar action, called actinism or chemical power, depends, probably, upon 

 the decreased length of the waves of the all-pervading fluid. The cause 

 of this phenomenon need not be explained here, further than the simple 

 statement that as the waves are shortened and approach in length to the 

 diameter of atoms, their power for disintegration increases. 



It was not the purpose of the Chair to indulge in a philosophical disqui- 

 sition in elucidation of these intricate subjects, but to explain a nomencla- 

 ture previously presented by him at the American Photographical Society, _ 

 which is designed to distinguish all the phenomena attending the action of 

 imponderable matter by names having a common root, and yet resembling 

 those now in general use sufficiently to prevent any misconception with 

 regard to their meaning. The greatest impediment to the progress of 

 science, thus far, has been the use of terms not easily remembered. The 

 nomenclature of Lavoisier, although far from perfect, has contributed more 

 than any one change towards the dissemination of chemical knowledge; 

 on the other hand botany is still obscured by terms, because it is now more 

 difficult to remember the names than the nature of plants. 



Matter is wholly comprised in two classes, ponderable and imponderable. 

 That having weight and bulk, exists either in a solid, liquid or gaseous 

 state; but that which can neither be weighed nor measured cannot be dis- 

 tinguished by subdivisions. We can only assert that there is a subtle, 

 imponderable, impalpable, elastic fluid pervading all space, as the con- 

 necting medium between celestial bodies, and permeating all ponderable 

 substances, filling the pores, so to speak, and connecting atom with atom, 

 as, in a far more rarified form, it connects star with star. • This fluid has 

 been distinguished by the term ether, derived from a Latin word, which 

 means shining, but the same word ether is used in chemistry to designate 

 volatile substances, ahd particularly that which consists of four atoms of 

 carbon, five of hydrogen and one of oxygen. It is proposed to use only a 

 part of the original Latin word, and to restore the dipthong oe, so that this 

 peculiar fluid will be distinguished by a name radically different from all 

 others, ajth. To pronounce this word requires the forcing of the breath 

 through a passage partially closed by the pressure of the tongue upon the 



