1. Dr. Bradley, like Kircher, considers his mirrors as applicable to regular figures, such as are represented in Fig. 55, and was entirely unacquainted with the fact, that the inclination of the mirrors must be an _even_ aliquot part of a circle. This is obvious, from his stating that the mirrors may be set at the _third_, fourth, _fifth_, sixth, _seventh_, or eighth part of a circle; for if he had tried to set an irregular object between the mirrors when placed at the _third_, _fifth_, or _seventh_ part of 360°, he would have found that a complete figure could not possibly be produced. 2. From the erroneous position of the eye in front of the mirrors, there is such an inequality of light in the reflected sectors, that the last is scarcely visible, and therefore cannot be united into a uniform picture with the real objects. 3. As the place of the eye in Bradley’s instrument is in front, and therefore much nearer the object, or sector, seen by direct vision, the angular magnitudes of all the different sectors are different, and hence they cannot unite into a symmetrical figure. This is so unavoidable a result of the erroneous position of the eye—a position too, rendered necessary from the absurd form of the mirrors—that Bradley actually employs his mirrors to convert a circle into an ellipse, and a square into a rectangle! 4. In Bradley’s instrument, the sectors thus unequally shaped, and unequally illuminated, are all separated from one another, by a space equal to the thickness of the glass plates; and from the same cause, the images reflected from the first surface interfere with those reflected from the second, and produce a confusion or overlapping of images entirely incompatible with a symmetrical picture. These results are deduced upon the supposition that the object consists of lines drawn upon the surface of paper, the only purpose to which Bradley ever applied his mirrors; but when we attempt to use these mirrors as a Kaleidoscope, and apply them to the objects which are usually adapted to that instrument, we shall fail entirely, as the mirrors are utterly incapable of producing the beautiful and symmetrical forms which belong to that instrument.