Experiments and considerations touching colours first occasionally written, among some other essays to a friend, and now suffer'd to come abroad as the beginning of an experimental history of colours / by the Honourable Robert Boyle ...

THE CONTENTS.

CHAP. I. THe Author shews the Reason, first of his Writing on this Subject (1.) Next of his present manner of Handling it, and why he partly declines a Methodical way (2.) and why he has partly made use of it in the History of Whiteness and Blackness. (3.)

Chap. 2. Some general Considerations are pre∣mis'd, first of the Insignificancy of the Observa∣tion of Colours in many Bodies (4, 5.) and the Importance of it in others (5.) as particularly in the Tempering of Steel (6, 7, 8.) The rea∣son why other particular Instances are in that place omitted (9.) A necessary distinction about Co∣lour premis'd (10, 11.) That Colour is not Inhe∣rent in the Object (11.) prov'd first by the Phantasms of Colours to Dreaming men, and Lu∣naticks; Secondly by the sensation or apparition of Light upon a Blow given the Eye or the Distemper

of the Brain from internal Vapours (12.). The Author recites a particular Instance in himself; another that hapn'd to an Excellent Person related to him (13.) and a third told him by an Inge∣nious Physician (14, 15.) Thirdly, from the change of Colours made by the Sensory Disaffected (15, 16.) Some Instances of this are related by the Author, observ'd in himself (16, 17.) others told him by a Lady of known Veracity (18.) And others told him by a very Eminent Man (19.) But the strange Instances afforded by such as are Bit by the Tarantula are omitted, as more properly deliver'd in another place. (20.)

Chap. 3. That the Colour of Bodies depends chiefly on the disposition of the Superficial parts, and partly upon the Variety of the Texture of the Object (21.) The former of these are confirm'd by several Persons (22.) and two Instances, the first of the Steel mention'd before, the second of melted Lead (23, 24.) of which last several Observables are noted (25.) A third Instance is added of the Porousness of the appearing smooth Surface of Cork (26, 27.) And that the same kind of Porousness may be also in the other Colour'd Bodies; And of what kind of Figures, the Super∣ficial reflecting Particles of them may be (28.) and of what Bulks, and closeness of Position (29.) How much these may conduce to the Generation of Colour instanc'd in the Whiteness of Froth, and in the mixtures of Dry colour'd Powders (30.) A further explication of the Variety that may be in the Superficial parts of Colour'd Bodies, that may cause that Effect, by an example drawn from the Surface of the Earth (31.) An Apology for

that gross Comparison (32.) That the appear∣ances of the Superficial asperities may be Varied from the position of the Eye, and several Instances given of such appearances (33, 34, 35.) That the appearance of the Superficial particles may be Varied also by their Motion, confirm'd by an Instance of the smoaking Liquor (35.) espe∣cially if the Superficial parts be of such a Nature as to appear divers in several Postures, explain'd by the variety of Colours exhibited by the shaken Leaves of some Plants (36.) and by change∣able Taffities (37, 38, 39.) The Authors wish that the Variety of Colours in Mother of Pearl were examin'd with a Microscope (40.) And his Conjectures, that possibly good Microscopes might discover those Superficial inequalities to be Real, which we now only imagine, with his reasons drawn partly from the Discoveries of the Teles∣cope, and Microscope (41.) And partly also from the Prodigiously strange example of a Blind man that could feel Colours (42.) whose History is Related (43, 44, 45.) The Authors conje∣cture and thoughts of it (46, 47, 48, 49.) and several Conclusions and Corollaries drawn from it about the Nature of Blackness and Black Bodies (50, 51, 52.) and about the Asperities of seve∣ral other Colour'd Bodies (53.) And from these, and some premis'd Considerations, are propos'd some Conjectures; That the reason of the several Phae∣nomena of Colours, afterwards to be met with, depends upon the Disposition of the Seen parts of the Object (54.) That Liquors may alter the Colours of each other, and of other Bodies, first by their Insinuating themselves into the Pores, and

filling them, whence the Asperity of the Surface of a Body becomes alter'd, explicated with some Instances (55, 56.) Next by removing those Bodies, which before hindred the appearance of the Genuine Colour, confirm'd by several examples (57) Thirdly, by making a Fissure or Separa∣tion either in the Contiguous or Continued Parti∣cles of a Body (58.) Fourthly, by a Ʋnion or Conjunction of the formerly separated Particles; Illustrated with divers Instances of precipitated Bodies (59.) Fifthly, by Dislocating the parts, and putting them both into other Orders and Po∣stures, which is Illustrated with Instances (60, 61.) Sixthly, by Motion, which is explain'd (62.) And lastly, and chiefly, by the Ʋnion of the Saline Bodies, with the Superficial parts of another Body, whereby both their Bigness and Shape must necessarily be alter'd (63, 64.) Explain'd by Experiments (65, 66.) That the Colour of Bodies may be Chang'd by the concurrence of two or more of these ways (67.) And besides all these, Eight Reflective causes of Colours, there may be in Transparent Bodies several Refractive (68, 69.) Why the Author thinks the Nature of Co∣lours deserves yet a further Inquiry (69.) First, for that the little Motes of Dust exhibited very lovely Colours in a darkned Room, whilst in a con∣venient posture to the Eye, which in other Postures and Lights they did not (70.) And that though the smaller Parts of some Colour'd Bodies are Trans∣parent, yet of others they are not, so that the first Doubt's, whether the Superficial parts create those Colours, and the second, whether there be any Re∣fraction at all in the later (71, 72, 73.) A

famous Controversie among Philosophers, about the Nature of Colour decided. (74. 75.)

Chap. 4. The controversie stated about Real and Emphatical Colours (75, 76.) That the great Disparity between them seems to be, partly their Duration in the same state, and partly, that Genuine Colours are produc'd in Opacous Bodies by Reflection, and Emphatical in Transparent by Refraction (78.) but that this is not to be taken in too large a Sense, the Cautionary instance of Froth is alleged and insisted on (78, 79.) That the Duration is not a sufficient Characteristick, exemplify'd by the duration of Froth, and other Emphatical Colours, and the suddain fading of Flowers, and other Bodies of Real ones (80.) That the position of the Eye is not necessary to the discerning Emphatical Colours, shew'd by the seeing white Froth, or an Iris cast on the Wall by a Prism, in what place of the Room soever the Eye be (81.) which proceeds from the specular Re∣flection of the Wall (82.) that Emphatical Co∣lours may be Compounded, and that the present Discourse is not much concern'd, whether there be, or be not made a distinction between Real and Em∣phatical Colours. (83.)

Chap. 5. Six Hypotheses about Colour recited (84, 85) Why the Author cannot more fully Speak of any of these (86.) nor Acquiesce in them (87, 88.) What Pyrophilus is to expect in this Treatise (88, 89.) What Hypothesis of Light and Colour the Author most inclines too (90.) Why he thinks neither that nor any other sufficient; and what his Difficulties are, that

make him decline all Hypotheses, and to think it very difficult to stick to any. (91, 92.)

Part the Second. Of the Nature of Whiteness and Blackness.

CHAP. I. THe reason why the Author chose the Expli∣cation of Whiteness and Blackness (93.) Wherein Democritus thought amiss of these (94.) Gassendus his Opinion about them (95.) What the Author approves, and a more full Explication of White, making it a Multiplicity of Light or Reflections (96, 97.) Confirm'd first by the Whiteness of the Meridian Sun, observ'd in Water (98.) and of a piece of Iron glowing Hot (99.) Secondly, by the Offensiveness of Snow to the Tra∣vellers eyes, confirm'd by an example of a Person that has Travell'd much in Russia (100.) and by an Observation out of Olaus Magnus (100.) and that the Snow does inlighten and clear the Air in the Night, confirm'd by the Mosco Physician, and Captain James (101.) But that Snow has no inherent Light, prov'd by Experience (102.) Thirdly, by the great store of Reflections, from white Bodies observ'd in a darkned Room, and by their unaptness to be Kindled by a Burning-glass (103.) Fourthly, the Specularness of White Bodies is confirm'd by the Reflections in a dark Room from other Bodies (104.) and by the ap∣pearance

of a River, which both to the Eye and in a darkned Room appear'd White (105. 106.) Fifthly, by the Whiteness of distill'd Mercury, and that of the Galaxie (107, 108.) and by the Whiteness of Froth, rais'd from whites of Eggs beaten; that this Whiteness comes not from the Air, shew'd by Experiments (109. 110.) where oc∣casionally the Whiteness of Distill'd Oyls, Hot water, &c. are shew'd (111.) That it seems not necessary the Reflecting Surfaces should be Sphaerical, confirm'd by Experiments (112, 113.) Sixthly, by the Whiteness of the Powders of trans∣parent Bodies (114.) Seventhly, by the Expe∣riment of Whitening and Burnishing Silver. (115. 116.)

Chap. 2. A Recital of some Opinions about Blackness, and which the Author inclines to (117.) which he further insists on and expli∣cates (118, 119.) and shews for what reasons he imbrac'd that Hypothesis (120.) First, from the contrary Nature of Whiteness and Blackness, White reflecting most Beams outwards, Black should reflect most inward (120.) Next, from the Black appearance of all Bodies, when Sha∣dow'd; And the manner how this paucity of Re∣fection outwards is caus'd, is further explicated, byshewing that the Superficial parts may be Coni∣ca and Pyramical (121.) This and other Con∣sidrations formerly deliver'd, Illustrated by Expe∣riments with black and white Marble (122, 123.) Thirdly, from the Black appearance of Holes in whit Linnen, and from the appearance of Velvet stroak'd several ways, and from an Observation

of Carrots (124, 125.) Fourthly, from the small Reflection from Black in a darkned Room (125, 126.) Fifthly, from the Experiment of a Checker'd Tile expos'd to the Sun-beams (127.) which is to be preferr'd before a Similar Expe∣riment try'd in Italy, with black and white Mar∣ble (128.) Some other congruous Observations (129.) Sixthly, from the Roasting black'd Eggs in the Sun (130.) Seventhly, by the Observa∣tion of the Blind man lately mention'd, and of another mention'd by Bartholine (130.) That notwithstanding all these Reasons, the Author is not absolutely Positive, but remains yet a Secker after the true Nature of Whiteness and Blackness. (131, 132.)

Experiments in Consort, touching Whiteness and Blackness.

The first Experiment, with a Solution of Subli∣mate, made White with Spirit of Urine, &c. (133, 134.)

The second Experiment, with an Infusion of Galls, made Black with Vitriol, &c. (135, 136) further Discours'd of (137.)

The third Experiment, of the Blacking of Hrts∣horn, and Ivory, and Tartar, and by a father Calcination making them White (138, 139.

The fourth Experiment, limiting the Chmist's principle, Adusta nigra sed perusta a••a, by several Instances of Calcin'd Alabaster Lead,

Antimony, Vitriol, and by the Testimony of Bel∣lonius, about the white Charcoles of Oxy-caedar, and by that of Camphire (140, 141, 142.) That which follows about Inks was misplac'd by an Errour of the Printer, for it belongs to what has been formerly said of Galls (142, 143.)

The fifth Experiment, of the black Smoak of Cam∣phire (144.)

The sixth Experiment, of a black Caput Mor∣tuum, of Oyl of Vitriol, with Oyl of Worm-wood, and also with Oyl of Winter-Savory (145.)

The seventh Experiment, of whitening Wax (146.)

The eighth Experiment, with Tin-glass, and Sublimate (147, 148.)

The ninth Experiment, of a Black powder of Gold in the bottom of Aqua-fortis, and of the Blacking of Refin'd Gold and Silver (148, 149.)

The tenth Experiment, of the staining Hair, Skin, Ivory, &c. Black, with Crystals of Silver (150, 151.)

The eleventh Experiment, about the Blackness of the Skin, and Hair of Negroes, and Inhabi∣tants of Hot Climates. Several Objections are made, and the whole Matter more fully discours'd,

and stated from several notable Histories and Ob∣servations (from the 151 to the 167.)

The twelfth Experiment, of the white Pow∣ders, afforded by Precipitating several Bodies, as Crabs Eyes, Minium, Coral, Silver, Lead, Tin, Quick-silver, Tin-glass, Antimony, Ben∣zoin, and Resinous Gumms out of Spirit of Wine, &c. but this is not Universal, since other Bo∣dies, as Gold, Antimony, Quick-silver, &c. may be Precipitated of other Colours (168, 169, 170.)

The thirteenth Experiment, of Changing the Blackness of some Bodies into other Colours (171, 172.) and of Whitening what would be Minium, and Copper, with Tin, and of Copper with Arsnick, which with Coppilling again Va∣nishes; of covering the Colour of that of ⅔ of Gold with ⅔ of Silver melted in a Mass together (173, 174.)

The fourteenth Experiment, of turning the black Body of Horn into a White immediately with Scraping, without changing the Substantial form, or without the Intervention of Salt, Sulphur, or Mercury (176.)

The fifteenth Experiment, contains several In∣stances against the Opinion of the Chymists, that Sulphur Adust is the cause of Blackness, and the whole Matter is fully discuss'd and stated (from 176 to 184.)

Part the Third. Concerning Fromiscuous Experiments about Colours.

Experiment the First. IN confirmation of a former Conjecture about the Generation of Colours from diversity of Reflections are set down several Observations made in a darkned Room (186, 187.)

Experiment the second, That white Linnen seem'd Ting'd with the Red of Silk plac'd near it in a light Room (188, 189.)

Experiment the third, Of the Trajection of Light through Colour'd Papers (189, 190.)

Experiment the fourth, Observations of a Prism in a dark Room (191, 192.)

Experiment the fifth, Of the Refracting and Reflecting Prismatical Colours in a light Room (193.)

Experiment the sixth, Of the Vanishing of the Iris of the Prism, upon the access of a greater ad∣ventitious Light (194.)

Experiment the seventh, Of the appearances of the same Colour'd Papers by Candle-light (195, 196.)

Experiment the eighth, Of the Yellowness of the Flame of a Candle (197.)

Experiment the ninth, Of the Greenish Blew transparency of Leaf Gold (198.)

Experiment the tenth, Of the curious Tin∣ctures afforded by Lignum Nephriticum (from 199 to 203.) Several trials for the Investiga∣tion of the Nature of it (from 204 to 206.) Kircher's relation of this Wood set down, and examin'd (from 206 to 212.) A Corollary on this tenth Experiment, shewing how it may be applicable for the Discovering, whether any Salt be of an Acid, or a Sulphureous, and Alcalizate Nature (from 213 to 216.)

The eleventh Experiment, Of certain pieces of Glass that afforded this Variety of Colours; And of the way of so Tinging any Plate of Glass with Silver (from 216 to 219.)

The twelfth Experiment, Of the Mixing and Tempering of Painters Pigments (219, 220, 221.)

The thirteenth Experiment, Of compounding several Colours by Trajecting the Sun-beams through Ting'd Glasses (from 221 to 224.)

The fourteenth Experiment, Of the Compound∣ing of Real and Phantastical Colours, and the Re∣sults (224, 225, 226.) as also the same of Phantastical Colours (226, 227.)

The fifteenth Experiment, Of Varying the Trajected Iris by a Colour'd Prism (228, 229.)

The sixteenth Experiment, Of the Red fumes of Spirit of Nitre, and the resembling Redness of the Horizontal Sun-beams (230, 231.)

The seventeenth Experiment, Of making a Green by nine Kinds of Compositions (from 231 to 236.) And some Deductions from them against the necessity of recurring to Substantial forms and Hypostatical principles for the production of Co∣lours (from 237 to 240.)

The eighteenth Experiment, Of several Compo∣sitions of Blew and Yellow which produce not a Green, and of the production of a Green by other Colours (241, 242.)

The nineteenth Experiment, contains several In∣stances of producing Colours, without the alte∣ration of any Hypostatical principle, by the Prism, Bubbles, and Feathers (from 242 to 245.)

The twentieth Experiment, Of turning the Blew of Violets into a Red by Acid Salts, and to a Green by Alcalizate (245, 246.) and the use

of it for Investigating the Nature of Salts (247, 248.)

The one and twentieth Experiment, of the same Changes effected by the same means on the Blew Tinctures of Corn-flowers (249, 250.) And some Restrictions to shew it not to be so general a propriety as one might imagine (251.)

The twenty second Experiment, of turning a Solution of Verdigrease into a Blew, with Alca∣lizate and Urinous Salts (252, 253, 254.)

The twenty third Experiment, of taking away the Colour of Roses with the Steams of Sulphur, and heightning them with the Steams Condens'd into Oyl of Sulphur per Campanam (254, 255.)

The twenty fourth Experiment, of Tinging a great quantity of Liquor with a very little Ting'd Substance, Instanced in Cochineel (from 255 to 257.)

The twenty fifth Experiment, of the more ge∣neral use of Alcalizate and Sulphureous Salts in the Tinctures of Vegetables, further Instanced in the Tincture of Privet Berries, and of the Flowers of Mesereon and Pease (from 257 to 259.) An Annotation, shewing that of the three Hypostatical principles, Salt according to Pa∣racelsus is the most, active about Colours (from 259 to 261.) Some things Praecursory premis'd

to three several Instances next following, against the fore-mention'd Operations of Salts (261, 262.)

The twenty sixth Experiment, containing Trials with Acid and Sulphureous Salts on the Red Tinctures of Clove-july-flowers, Buck thorn Berries, Red-Roses, Brasil, &c. (262, 263.)

The twenty seventh Experiment, of the chan∣ges of the Colour of Jasmin flowers, and Snow drops, by Alcalizate and Sulphureous Salts (263, 264.)

The twenty eighth Experiment, of other differ∣ing Effects on Mary-golds, Prim-roses, and fresh Madder (265.) with an Admonition, that these Salts may have differing Effects in the changing of the Tinctures of divers other Vegetables (266, 267.)

The twenty ninth Experiment, of the differing Effects of these Salts on Ripe and Unripe Juices, instanced in Black-berries, and the Juices of Roses (from 267 to 270.) Two reasons, why the Au∣thor added this twenty ninth Experiment, the last of which is confirm'd by an Instance of Mr. Par∣kinson, consonant to the Confession of the Makers of such Colours (272.)

The thirtieth Experiment, of several changes in Colours by Digestion, exemplify'd by an Amal∣gam of ☉ and ☿ and by Spirit of Harts-horn. And (to such as believe it) by the changes of the Elixir.

The thirty first Experiment, shewing that most Tinctures drawn by Digestion incline to a Red, instanc'd in Jalap, Guaicum, Amber, Benzoin, Sulphur, Antimony, &c. (276, 277.)

The thirty second Experiment, That some Reds with Diluting turn Yellow, others not, exemplify'd by the Tincture of Cochineel, and by Balsam of Sulphur, Tinctures of Amber, &c. (277, 278, 279.)

The thirty third Experiment, of a Red Tin∣cture of Saccarum ♄ and Oyl of Turpentine made by Digestion (279.)

The thirty fourth Experiment, of drawing a Volatile red Tincture of Mercury, whose Steams were white, but it would Tinge the Skin black (279, 280.)

The thirty fifth Experiment, of a suddain way of making a Blood red Colour with Oyl of Vitriol, and Oyl of Anniseeds, two transparent Liquors (280, 281.)

The thirty sixth Experiment, of the Degene∣rating of several Colours exemplify'd in the last mention'd Blood red, and by Mr. Parkinsons relation of Turnsol, by some Trials with the Juice of Buck-thorn Berries, and other Vegeta∣bles, to which several notable Considerations and Advertisements back'd with Experiments are ad∣joyn'd (from 281 to 288.)

The thirty seventh Experiment, Of Varying the Colour of the Tinctures of Cochineel, Red∣cherries, and Brasil, with Acid and Sulphureous Salts, and divers Considerations thereon (from 288 to 290.)

The thirty eighth Experiment, About the Red fumes of some, and White of other distill'd Bodies, and of their Coalition for the most part into a transparent Liquor (290, 291.) And of the various Colours of dry Sublimations, ex∣emplify'd with several Experiments (292, 293, 294.)

The thirty ninth Experiment, Of Varying the Decoction of Balaustiums with Acid and Urinous Salts (294, 295.) Some Annota∣tions wherein two Experiments of Gassendus are Related, Examined, and Improv'd (from 295 to 302.)

The fortieth Experiment, Of the no less Strange than Pleasant changes made with a So∣lution of Sublimate (from 302 to 306.) The difference between a Chymical and Philosophical Solution of a Phaenomenon (307, 308.) The Authors Chymical Explication of the Phaeno∣mena, confirm'd by several Experiments made on Mercury, with several Saline Liquors (from 308 to 310.) An Improvement of the fortieth Experiment, by a fresh Decoction of Antimony in a Lixivium (311, 312, 313.) Reflections on the tenth, twentieth, and fortieth Experiments, compar'd together, shewing away with this Tin∣cture

of Sublimate to distinguish whether any Sa∣line Body to be examin'd be of a Urinous or Alca∣lizate Nature (from 314 to 317.) The Ex∣amination of Spirit of Sal-armoniack, and Spirit of Oak by these Principles (from 316 to 319.) That the Author knows ways of making highly Operative Saline Bodies, that produce none of the before mention'd Effects (319, 320.) Some notable Experiments about Solutions and Precipi∣tations of Gold and Silver (320, 321.)

The one and fortieth Experiment, Of Depri∣ving a deep Blew Solution of Copper of its Colour (322.) to which is adjoyn'd the Discolouring or making Transparent a Solution of Verdigrease, &c. and another of Restoring or Increasing it (322, 323.)

The forty second Experiment, Of changing a Milk white Precipitate of Mercury into a Yel∣low, by Affusion of fair Water, with several Considerations thereon (from 323 to 326.)

The forty third Experiment, Of Extracting a Green Solution with fair Water out of imperfectly Calcin'd Vitriol (327.)

The forty fourth Experiment, Of the Deep∣ning and Diluting of several Tinctures, by the Affusions of Liquors, and by Conical Glasses that contain'd them, Exemplify'd in the Tinctures of Cochineel, Brasil, Verdigrease, Glass, Litmus, of which last on this occasion se∣veral pleasant Phaenomena are related (from

328 to 335.) To which are adjoyn'd certain Cautional Corollaries (335, 336.) The Water-drinker and some of his Legerdemain tricks re∣lated (337.)

The forty fifth Experiment, Of the turning Rhenish and White Wine into a lovely Green, with a preparation of Steel (338, 339. Some further Trial made about these Tinctures, and a Similar Experiment of Olaus VVormius (340.)

The forty sixth Experiment, Of the Internal Colour of Metalls exhibittd by Calcination (341, 342, 343.) Annotation the first, That several degrees of Fire may disclose a differ∣ing Colour (343.) Annotation the second, That the Glasses of Metalls may exhibit also other Kinds of Colours (344.) Annotation the third, That Minerals by several degrees of Fire may disclose several Colours (345.)

Experiment the forty seventh, Of the Inter∣nal Colours of Metalls disclos'd by their Dissolu∣tions in several Menstruums (from 345 to 350.) Annotation the first, The Authors Apology for Recording some already known Experiments, without mentioning their Authors (from 350 to 352. Annotation the second, That some Mi∣nerals also by Dissolutions in Menstruums may exhibit divers Colours (353.) Annotation the third, That Metalls disclose other Colours by Precipitations, instanc'd in Mercury (from 353 to 355.)

The forty eighth Experiment, Of Tinging Glass Blew with Leaf Silver, and with Calcin'd Copper, and White with Putty (from 355 to 358.) Annotation the first, That this white Glass is the Basis of Ammels (358.) Anno∣tion the second, That Colour'd Glasses may be Compounded like Colour'd Liquors in Dying Fats (359.) Annotation the third, Of Tinging Glass with Mineral Substances, and of trying what Metalls they contain by this means (from 360 to 362.) Annotation the fourth, That Metalls may be Ting'd by Mineralls (362, 363.) Annotation the fifth, Of making several Kinds of Amauses or Counterfeit Stones (from 363 to 365.) Annotation the sixth, Of the Scarlet Dye, of the Stains of dissolv'd Gold and Silver (366, 367.) Of the Greenness of Salt Beef, and Redness of Neats Tongues from Salts; of Gilding Silver with Bathe Water (368, 369.) And Tinging the Nails and Skin with Alcanna (369)

The forty ninth Experiment, Of making Lakes (369.) A particular example in Tur∣merick (370, 371.) Annotation the first, That in Precipitations wherein Allum is a Co∣efficient, a great part of them may consist of the Stony particles of that Compound Body (from 372 to 375.) Annotation the second, That Lakes may be made of other Substances, as Madder, Rue, &c. but that Alcalizate Salts do not always Extract the same Colour of which the Vegetable appears (from 376 to 378.) Annotation the third, That the Experiments

related may Hint divers others (378.) An∣notation the fourth, That Alum is usefull for the preparing other than Vegetable Pigments (379.)

The fiftieth Experiment, Of the Similar effects of Saccarum ♄ and Alkalies, of Precipitating with Oyl of Vitriol out of Aqua-fortis, and Spirit of Vinegar; and of divers Varyings of the Colours, with these Compounded (from 380 to 384.) Ano∣ther very pretty Experiment, with a Solution of Minium (384, 385.) That these Experiments Skilfully digested may hint divers matters about Colours (386.) The Authors Apologetick con∣clusion, in which is Cursorily hinted the Bow or Scarlet Dye (387.) The Authors Letter to Sir Robert Moray, concerning his Observations on the Shining Diamond (391. &c.) And the Ob∣servations themselves.