326 ANNUAL OF* SCIENTIFIC DISCOVERY. 



And yet, though all is so far negative to us, we are not without 

 glimpses of the possible nature of a medium such as has been sup- 

 posed ; that is to say, if it exists at all, we may make an estimate 

 of certain of its properties. It is indestructible for one property, and 

 unchangeable ; by which we mean that it cannot be assumed to enter 

 into combination, and so to change its original type and character by 

 combination like a common combining elementary gas. As a sequence 

 to this view the ether must be considered as negative in character, per- 

 meating matter wheresoever it can gain entrance, and even perhaps 

 adding to the bulk of matter, and communicating to it motion under 

 external influence, but not combining with the parts of matter in any 

 definite bond. Sensitive to all external mechanical influence, it must 

 be susceptible of undulation to the highest degree, and, existing as 

 matter, must take the gaseous type, and represent that type in its 

 most refined ideal ; so as to evade, in fact, all our present means of 

 determining it, as material, by experiment ; and to be comprehensi- 

 ble only when, accepting for the argument's sake the undulatory 

 theory of light, we make a theoretical estimate of the undulations of 

 light by the side of those of sound. Then truly we may admit, with 

 Mr. Vaughan, that as the medium which conveys light conveys it 

 with nearly a million times the rapidity of sound, " such medium 

 must have a modulus of elasticity almost 1,000,000,000,000 as great 

 as that of common air." 



The reader will glean from these observations the immense difficul- 

 ties which lie in the way of demonstrating by physical means the 

 presence of the ether of space. But it would be very false argument 

 to condemn the theory of the existence of this ether on the ground 

 of the difficulty of demonstration. We will illustrate this by a single 

 observation. We will assume that it were revealed to us beyond con- 

 tradiction, by some superior intelligence, that an ethereal medium, 

 having, as Mr. Vaughan expresses it, " a modulus of elasticity 1,000,- 

 000,000,000 as great as common air," did exist around us ; we will 

 suppose that we were further informed that the gaseous medium thus 

 presented resembled one of our recognized bodies, having negative 

 properties, say, for example, nitrogen. Even then, with all our ap- 

 pliances, we should at this moment fail in being able to make a single 

 demonstration of the existence of such a medium. It would have to us 

 nor weight, nor volume, by which it could be distinguished, nor chemi- 

 cal agency, nor resistance that could be measured. Were we adven- 

 turous in science, we might declare a conviction that the ethereal 

 medium was a body negative like nitrogen ; in space refined ; but in 

 the neighborhood of planets, within the sphere where the specific 

 elasticity of air is equipoised by the force of gravity, more condensed, 

 and more closely resembling a gas, but as yet inappreciable. 



Finally, if there is an all-pervading ether, we are tempted to 

 inquire, Of what use is it ? The answer here is less difficult to name 

 than in the previous cases, but infinitely more prolonged if followed 

 to its end. If there is an all-pervading ether, its uses are equally all- 

 pervading, and are fitted rather to take description from the poet 

 than the philosopher. We must not attempt the task, but leave it 

 rather to the imagination to conceive, how a subtle bond connect- 

 ing sphere with sphere, man with man, and man with all that he sees 



