673 
Leeuwenhoek’s microfcopes, 6 it. 
Lead, its effedt in the formation of glafs, 
SSi* 
Lenfes, different kinds, and their properties, 
572-5 ; diredtions for grinding and polic¬ 
ing them, 598. 
Leflie’s photometer, 637. 
Eieberkuhn’s folar microfcope, 612, 20; mi- 
crol'cope for opaque objedts, 612. 
Light, as to the nature of, 546 ; refradtion 
of, 547; inflexion, 552 ; refledtion, 555; 
polarifation, 557-64; 592, 3 ; to meafure 
the intenfity of, 632 ; aberration produced 
by the different refrangibility of rays, 
658 ; by the fpherical form of reflecting 
and refradting furfaces, 661. 
Lowthorp’s experiments on refradtion, 548. 
Lucernal microfcopes, 621. 
Lyonet’s difl’edting microfcope, 616. 
Magic lantern, invented by Kircher, 544; 
its phenomena explained, 653. 
Malton, Thomas and James, writers on per¬ 
fpedtive, 663, 664. 
Malvafia’s micrometer, 624. 
IMalus, his difcovery of the polarifation of 
light, 558, 9 ; his lamented death, 560. 
Manton’s telefcope with an exhaufted tube, 
605. 
Marfhal, Mr. inventor of the double micro- 
feope, 616. 
Martin", Benjamin, his improvements on te- 
lefcope-glaffes, 6045 farther improved by 
Tulley, 605 ; his microfcope and megalo- 
fcope, bi6; his univerfal microfcope, 618 ; 
his micrometers for microfcopes, 630 ; his 
graphical perfpedtive, 671. 
Maikelyne’s prifmatic micrometer, 626. 
Maurolycus, 543, 544, 564, 594. 
Merlenne firft laid down the principle of the 
refledting telefcope, 601. 
Metius, James, the fuppofed inventor of the 
• telefcope, 544. 
Michel’s calculation of the light of the fun 
• and moon, 634. 
Micrometers, telefcopic, 624 ; improved by 
Wolfius and others, 625 ; with a divided 
objedt-glafs, 626, 657 ; prifmatic and 
catoptric micrometers, 626; dioptric, 6:7 ; 
imperfections of micrometers, 627, 8; Dr. 
Herfchel’s, 618 ; Smeaion’s, Brewfter’s, 
and Cavallo’s, 629 ; microfcopic microme¬ 
ters, 629-632 ; Adams’s, 630; Coventry’s, 
631,2; Breguet’s, 657. 
Microfcope, its invention foon followed that 
of the telefcope, 545 ; the author of the 
invention difputed, 611 ; as made by va¬ 
rious perfons, 611, 12; making the glafs 
Ipherules for, 612, 13 ; Angle microfcopes, 
613, 657; for opaque objedts, 614; by 
refledtion, 614, 15; water-microfcopes, 
615, j6; botanic, hand, and difiedting 
microfcopes, 616; compound microfcopes, 
616, 657; refledting, 619; folar, 620, 
657 ; luternal, 621 ; magnifying powers 
of, 624. 
Morichini difeovers a magnetic property in 
the violet rays, 592, 3. 
Mudge, his improvements in the fpecula of 
telefcopes, 602. 
Multiplying glafles, 599. 
Muriatic acid, Angular property of, 551. 
Nettleton, Dr. his obfervations on atmofphe- 
rical refradtion, 551, 2. 
Newton, his treatife on optics, 541, 1-47 ; 
dife- ’ers the nature of light, and the phe¬ 
nomena of colours, 549; his experiments 
on the infledtion of light, 556, 7 ; difeo¬ 
vers the prefent fyftem of colours, 591; 
OPTICS. 
and of the rainbow, 595 ; his refledting 
telefcope, 601, 653 ; improved, 602 ; re¬ 
fledting microfcope, 619; his explanation 
of the unequal refrangibility of the rays of 
light, 658, 9.. 
Noble’s perfpedtive, 663, 664. 
Optic glafles, manufadture of, for microfcopes, 
598, 612; for telefcopes, 609; to mend, 
610 ; fquare, 611. 
Optic nerve, calculation relating to, 586. 
Optical inftruments, 597-652 ; their pro¬ 
perties, 652 ; how to remedy their imper- 
fedtions, 658. 
Optics, ancient theories; viz. of Pythago¬ 
ras, Plato, Ariflotle, Epicurus, &c. of the 
mathematicians Euclid and Ptolemy, 541; 
in the middle ages, as Alhazen, 542 ; Vi- 
tellio, Peccam, Roger Bacon, &cj 543 ; 
moderns, as Maurolycus, B. Porta, Kir¬ 
cher, Kepler, Des Cartes, &c. 544 ; Snel- 
lius, Scheiner, Gaflendi, &c. 545 ; Kir¬ 
cher, Gregory, Barrow, Grimaldi, Huy¬ 
gens, &c. 546; Newton, 547; fucceflive 
difeoveries on refradtion, 547, 567; reflec¬ 
tion, 552; inflexion, 555 ; polarity of light, 
557 ; vifion, 561 ; colours, 592. Con- 
ftrudtion of inlfruments, 597 ; properties 
of ditto, 652; imperfedlions of ditto, 658. 
Optometer, or meafurer of fight, 638. 
Peccam, archbilhop of Canterbury, 543. 
Perfpedtive, a general name for diredt optics, 
543 ; for optics in general, 663 ; hiftory 
of perfpedtive, and writings upon it, 663, 
4; fundamental theorem, as to figures in 
a horizontal plane, 664; fundry pradtical 
rules, 665 ; of figures not in a horizontal 
plane, 666 ; of folid figures, 667; of dif- 
torted figures, 668, 9 ; inftruments ufed 
in perfpedtive, 669. 
Phantafmagoria and phantafmafeope, 653. 
Photometer, or meafurer of light, by M. 
Bouguer, 632 ; by count Rumford, 634 ; 
by M. de dauflure, 636, 7 ; by Leflie, 
637. 8._ 
Plato was acquainted with two fundamental 
principles of optics, 541. 
Polarifation of light, a late difcovery, 557 ; 
firft noticed by M. Malus, 558 ; the in¬ 
quiry continued by Biot, 560 ; and by Dr. 
Brewfter, 560-64. 
Porta, Baptifta, inventor of '.he camera ob- 
feura, 543. 
Porterfield, Dr. his theory of vifion, 564, 5, 
585 ; inventor of the optometer, 638. 
Prifm, the divifion of the rays of light not 
fimilar to the mufical chord, 659. 
Ptolemy’s treatife on optics difeovered, 542 ; 
his theory of refradtion, 547. 
Pythagoras, his idea of the nature of vifion, 
54 f - 
Rainbow, Alhazen’s account of it, 543; its 
true nature hit upon by Antonio de Do- 
minis, 544, 594; mathematically ex¬ 
plained, 593-6. 
Ramfden’s catoptric micrometer, 626 ; diop¬ 
tric, 627. 
Rand’s micrometrical telefcope, 605. 
Reader’s new theory of light and colours, 
591,2. 
Refledtion of light, difeoveries relating to, 
552 ; theory of, 575. 
Refradtion of light, treated of by Kepler, 
but its true law difeovered by Snellius, 
but more fully by Des Cartes, 545; far¬ 
ther account of difeoveries in refradtion, 
547, 8 ; by Grimaldi, fir Ifaac Newton, 
and Mr. Dollond, 549; Dollond, Euler, 
Clairault, and d’Alembert, 550; Zeiher 
and Dr. Blair, 551; atmofpheric refrac¬ 
tion, 551, 2 ; double refradtion, or pola¬ 
rifation, 557-564; theory of refradtioij, 
567 575 ; table of refradtive denfities, 56$ ; 
angle of incidence and refradtion mathe¬ 
matically explained, 568 ; by plane fur- 
faces, 569 ; by fpherical furfaces, 570. 
Rheita’s terreftrial telefcope, 600. 
Rondoni’s patent telefcope, 605. 
Rumford, count, his photometer, 634; me¬ 
thod of ufing it, 635 ; farther experiments, 
637. 
Sauffure’s improvements on the intenfity of 
light, 636 ; his diaphanomctc-r, 637. 
Scheiner, his improvements of the telefcope, 
545 ; difeoveries as' to the phenomena of 
vifion, 546 ; his aftronomical telefcope, 
600. 
Short’s refledting telefcopes, 602. 
Smith, Dr. his work on Optics, 547 ; bis ex¬ 
periments on vifion, 566 ; his refledting 
microfcope, 619 ; his calculation of the 
moon’s light as compared with that of the 
fun, 633, 4; his anamorphofi;, 669. 
Snellius fiift difeovers the law of refradtion, 
545 > 54 s - . 
Spedtacles firft hinted at by Roger Bacon, 
543 - 
Taylor, Dr. Brook, his Treatife on Per¬ 
fpedtive, 663, 4. 
Telefcope, firft invention of difputed, 544, 
599, 600 ; improved by Galileo and 
Scheiner, 545, 600 ; by Kspder, Cavel- 
lieri, Rheita, Huygens, Azout, &c. 600 ; 
vuft length of fome of thefe telefcope?, 
ibid, corredted by Newton, 6oo, I ; the 
various kinds of refledting telefcopes com¬ 
pared, 601 ; Short’s, and Ramfden’s, and 
Edwards’s, telefcopes, 602 ; Dollond’s re¬ 
fradting achromatic telefcopes, 6.C2, 3; 
Martin’s, and Tulley’s, 604 ; Rand’s, 
Adam’s, Brown’s, Manton’s. Varley’s, and 
Rondoni’s, 605, Herfchel’s, 608 ; con- 
ftrudtion, or fitting-up, of telefcopes, 605 ; 
choice of, 610,11; properties of, 653; 
imperfedlions of, 658. 
Telefcope-glafles, how to caft, polifh, &c. 
609 ; to mend, 610. 
Tulley’s improved objedt-glaflfes for tele¬ 
fcopes, 604 ; telefcope-ftands, 607. 
Varley’s graphic telefcope, 605. 
Ubaldi’s difeoveries in perfpedtive, 6G3. 
Vifion, fome of the laws of, firft explained 
by Kepler, 544 ; other difeoveries, 564; 
Angle vifion with two eyes, accounted lor 
by Dr. Porterfield, 564, 5; by Dr. Reid 
and Dr. Wells, 565, 6-7 ; curious experi¬ 
ments of Dr. Juiin and Dr. Smith, 566; 
Epinus, 566, 7 ; theory of vifion, and the 
propofitions depending thereon, 581-593. 
Vitello, a commentator 0,1 Alhazen, 542, 3. 
Vitruvius’s notices of perfpedtive, 663. 
Water-microfcopes by Grey and Ellis,.615. 
Wells, Dr. his theory of Angle vifion, 565. 
Wilfon’s microfcopes, 611, 613. 
Vf ithering’s botanical microfcope, 616. 
Wolf’s rules for putting a circle in perfpec- 
tive, 667. 
Wolfius’s micrometer, 625. 
Woollafton, Dr. his experiments on the pro¬ 
perties of Iceland fpar, 558 ; his camera 
lueida, for fketching views in right per¬ 
fpedtive, 670. 
Young’s improved optometer, or meafurer of 
fight, 638. 
Zeiher, his experiments as to the eompofuion 
of glafs for telefcopes, 550; improvement 
in microfcopes, 6:2. 
8 I 
Vol. XVII. No. 1207. 
