Porta, Giambattista della, 1535?-1615 · London : Printed for Thomas Young, and Samuel Speed, and are to be sold at the three Pigeons, and at the Angel in St. Paul's Church-yard · leaf 391
fame is to be faid of the beam M H andNG, and this Glafs is contrary to a Sphseral Glafs : From divers points of the circumference, the rays are reflefted upon different parts of the diameter, and all the diameters are from the Centre: but in this the refle&ed beams unite, not in one point, and the… … Chap. XIX. Fire is kindled wore forcible by ref '•allion. IHave fpokenof Burning-glaffes by reflexion : Now I (ball fpeak of thofe which burn by refra&ion • for thefe kindle fire more violently , I (hall ffiew tny reafon in the Opticks^ Wherefore By a Cylindre of Cryfial to kindle fire . We may do…
Science -- Early works to 1800 · Magic · Alchemy · Industrial arts -- Early works to 1800
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