202 NATURE AND MAN. 



alone a correct notion of its solid form t there is adequate evidence 

 that this notion, also, is a mental Judgment based on the experience 

 we have acquired in early infancy by the consentaneous exercise 

 of the visTial and tactile senses. 



Take, again, the case of those wonderful instruments by which 

 our visual range is extended almost into the infinity of space, or 

 into the infinity of minuteness. It is the mental not the bodily 

 eye, that takes cognizance of what the telescope and microscope 

 reveal to us. For we should have no well-grounded confidence 

 in their revelations as to the unknown, if we had not first acquired 

 experience in distinguishing the true from the false by applying 

 them to known objects ; and every interpretation of what we see 

 through their instrumentality is a mental judgment as to the prob 

 able form, size, and movement of bodies removed by either their 

 distance or their minuteness from being cognosced by our tactile 

 sense. 



The case is still stronger in regard to that last addition to 

 our scientific armamentum, which promises to be not inferior in 

 value either to the telescope or the microscope; for it may be truly 

 said of the spectroscope, that it has not merely extended the range 

 of our vision, but has almost given us a new sense, by enabling 

 us to recognize distinctive properties in the chemical elements 

 which were previously quite unknown. And who shall now say 

 that we know all that is to be known as to any form of matter ; 

 or that the science of the fourth quarter of this century may not 

 furnish us with as great an enlargement of our knowledge of its 

 properties, and of our power of recognizing them, as that of its 

 tliird has done ? 



But, it may be said, is not this view of the material universe 

 open to the imputation that it is evolved out of the depths of 

 our own consciousness &quot; a projection of our own intellect into 

 what surrounds us an ideal rather than a real world ? If all 

 we know of matter be an &quot; intellectual conception,&quot; how are 

 we to distinguish this from such as we form in our dreams ? 

 for these, as our Laureate no less happily than philosophically 

 expresses it, are &quot;true while they last.&quot; Here our &quot;common 

 sense&quot; comes to the rescue. We &quot;awake, and behold it was 

 a dream.&quot; Every healthy mind is conscious of the difference 



