8 9

Optics.

*car the ^-- 0 l' ar >s fixed a Tube of Brass C,

Outside" h nches ^ Diameter ; the End of which on thet hrov k - n ’ as . a convex L~ns 5 to collect the Sun-Beamst0vV ?.rds '°5 r . the Glass G, and converging themflidh lp .: a ^cus in the other Part, where D is a Tubehoni t !, n out, to adjust the Object to a due Distanceis fctewV! ° CUS ' T 0 the End G of another Tube F^inirip- th 0 ^ ^*s on ’ 5 Single Pocket Microscopes , con-

tfie 0 Object to be magnified in a Slider; and by1’ubc f) C • ’. Aiding on the small End E of the otheriq, -p, 11 * s brought to a due focal Distance,

W Mici- r great Atdfice and Conveniency of this So-°Miq Ue j? c °P e is, that by means of the Glass G the<Wlc n la y s of the Sun are made to go strait along the°n it, 't -? 1 Parallel to the Floor, instead of falling up-Glass, a))( j U * ict A B denote a Section of the Looking-*C, b v the Rays of the Sun impinging upon it• 0n Uheri 1C ^ are reflected to the Lens D, andto fog 6 c °nverged towards E to illuminate theOb-hvkn C t ? a § n iAed ; so that the Beam of Light goesTad nf o ,E m the Direction parallel to the Floor, in-l S on it in the Direction S G. By the

r aa of f.,)T- •“

* Ulley . lln g Oil 1C III mi; --— , —

°y the , • the Glass is turned directly to the Sun, andPtess’d nte d Wire and Screw at H it is elevated or de-ttfluired ° as to bring the Glass into the Position A Bl ° th e & W * lere the Angle of Incidence A C S is equal\ ru Sia n p gle of Reflection BCE. Mr. Liburkun, a,Method V en tleman, was the first who invented thisIT-Glaf? ma gnifying Objects, but without the Look-t'heory ’ tfthich was afterwards added to it. ThetM s artle _ this Contrivance and the Magic Lanthorn isCandje here we make use of Sun-Beams instead

of file Cm I, and the Object and magnifying Lens20. A 4 u Size -

have r, <)t ler toost egregious Contrivance of this SortC; dls b\??v, ^ 1C ^ ate learned Dr. s’Gravesande , whichPetty 0 f I . Name of Heliostata, from its Pro-r°'b viz ,n‘ n ^ [ AS *t were) the Sun-Beam in one Posh

. 5 v « IS were) r»e ^""'^?darkCham

TTT*. in an horizmtalDiretHon ^acrossth- ....

w r Al the while it is in Use. Itle «e of Clock-work, whose Part, _, um Z is fits'S a Frame jp which a metalline Sp

is an Automaton, or pj a£e pj:s are as follow. AA

pendpd,