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Lamp,though not to so great a degree. The Figure on paper,or L smooth white surface is not magnified enough, nor thedifference of shadows so very distinct, though that doth verywell, if the surface be very smooth, and the Object be magni-fied by a Hand Glass. That by the contracted Aperture is theworst of all, by reason of a certain propriety of Light nottaken notice of yet by Optiek Writers, the edges of Ob-jects seeming ragged, of which I have hinted somewhat in myjinimadverflons^pag. 35, and shall shortly say much more, thewhole ground of Of ticks depending thereon.

The way of expanding the figure of the Sun by the EyeGlass, to me seems the best os all the rest, but that is apt tovitiate the Figure, to super-induce somewhat of Colour, anddoth not give the smallest distinctions of lights and shadows,without somewhat of colour, and somewhat of haziness anddimness.

The Glasses of this HELIOSCOPE may be made ei-ther by refracting or resecting Spherical Glasses. The best wayfor taking in a large Angle, is, the using refracting Glasses,both for the Object and Eye Glasses; but the best way fortaking in a small part, and for avoiding haziness, dimness, andcolours, is, by Reflection, either in part, or in whole ; thatis, either to make the Object Glass only by way of Refle-ction, and the Eye Glass by that of Refraction , or, both theObject-glass and Eye Glass also by reflection, and to have norefraction at all. The several waies of doing which I haverepresented in the adjoyning Table, wherein 1 have expressedten several waies of placing the several Glasses, so as to be fitfor the use designed.

The first way represented in the first Figure, is, a sixty footObject-Glass, contracted into a twelve foot Tube, by the helpof four several Reflecting-plates placed between the Object-Glass and Eye-Glass. The Experiment of doing which, Iproduced and shewed before the Royal Society , at divers oftheir publick Meetings at jtrundel house, in the year 1668,and it remains upon their Register.

This (as I then shewed) would be of exceeding great usei n all manner of PerspeCtives and telescopes , if we could finda good material that would make the Reflections very strong

and