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162) 
the former, in giving polarity to it, or recersing that which is had already acquired, the latter in very sensibly disturbing its direction. We have observed likewise another point of resemblance between them, which has not been noticed b the author, nor, we believe, by other writers: we mean the transparency of the electric fluid, evinced by the facility with which a small luminous body is seen through a stream of electric matter [[underline]] in vacuo [[/underline]], not withstanding the seeming opacity of the latter. The small speck of light, for instance, remaining on the tip of a very small wax taper, after the flame is extinguished, (and which in some kinds will continue burning a considerable time) is as distinctly perceived through a dense luminous [[strikethrough]] col [[/strikethrough]] column of electric light, passing from the wire of a charged vial, and flowing through the [[underline]] vacuum [[/underline]] in the upper part of a barometer of a large bore, as when it is viewed through the tube, when the electric light no longer passes through it; and does not ill represent a fixed star seen either through the [[underline]] Aurora Borealis [[/underline]] or the tail of a comet. The light proceeding from a small piece of [[underline]] Phosphorus [[/underline]], though more lasting, is not so well adapted to this experiment; as being of the same colour with the electric light, and accordingly not easily to be distinguished from it."
[[margin]] An Objection. [[/margin]] This experiment, at best, is very precarious, for our senses are not capable of Judging the transparency of the medium, and the brilliancy of [[strikethrough]] the [[/strikethrough]] a luminous object seen thro' it, is so nice a case. But I am certain from my own experience, it is not true in the matter of fact which it is brought to illustrate; for a fixed Star seen thro' a strong [[underline]] Aurora Borealis [[/underline]] is never so bright as when there is none. It is well known that mists, exhalations, &c. obstruct the brilliancy of luminous objects, and if one medium has this effect, why not another. - This experiment of the Reviewers, if true, confirms Jones's opinion about sound not being obstructed by Winds, &c. and the easy penetrability of one fluid through another, at p. 271, &c. of his [[underline]] Essay on the first principles of ^ [[insertion]] natural [[/insertion]] philosophy [[/underline]].