CELESTIAL MEASURINGS AND WEIGHINGS. 215 



enormous distance which separates the sun from the 

 nearest fixed star affords a still more complete guarantee 

 against the possibility of any disturbance of the plane- 

 tary movements by their attraction, and may not un- 

 naturally be considered as so intended. A continuance 

 of the same system of precaution (if we may venture on 

 the use of such a word) against external influence, into 

 the mutual relations of sidereal systems might therefore 

 lead us to expect that the intervals between them would 

 at least bear some very large proportion to the extent of 

 each. That there exist instances of nebulae which appear 

 to be bound together by a kind of companionship similar 

 to that of the double stars, does not in the least invalidate 

 this as a general conclusion. Here, however, figures 

 avail us nothing. Nor can it be necessary, after what 

 has been already said, to stimulate our imaginations to 

 any further effort to grasp and comprehend distances 

 and magnitudes inconceivable by man. Suffice it that 

 in the dim glimpse thus caught of an immensity of mate- 

 rial existence stretching outward by steps continually 

 more and more gigantic, we carry with us not a mere 

 general impression, but a well-founded conviction 

 grounded on an induction from observed facts of mea- 

 surement and computation, that the same mechanical 

 laws at least ; the same relation between matter, force, 

 and motion as those we see in action around us, prevail 

 in the uttermost regions of space ; and regulate, there as 

 here, the evolutions of the systems disseminated through 

 it In the endless variety of combination exhibited 

 among the double stars too (to say nothing of a multi- 



