Some Observations, Touching Colours, in Order to the Increase of Dyes, and the Eixation of Colours; Generously Imparted by the Author of the Four Above-Mention'd Letters, Who Annexed Them to That of Februar. 15. 1670

more the growth of the Tree; since everything grows in proportion to the Root beneath: But I am doubtful in this, whether I do well or ill, and desire the judgement of others. For, I have heard from some Planters, and afterwards from a Knight who had experience therein, that Roots cut short doe best, as sending forth New roots, which draw sap and nourishment best. And we see that Moyles set on slips that have no roots, come to a Tree sooner. And I have oft observed, that a Moyle Transplanted after it hath taken root does not live so certainly, or thrive so well as a slip newly set. But I have gone beyond the bounds of a Letter. This Letter being imparted to an Ingenious Inquirer into such things, he was pleased to return some of his considerations thereupon, which are like to be published in our next. Some Observations, touching Colours, in order to the Increase of Dyes, and the Fixation of Colours; generously imparted by the Author of the Four above-mention'd Letters, who annexed them to that of Februari. 15. 1670. Two things, I conceive, are chiefly aimed at in the Inquiry of Colours, which subject you desire my thoughts of; the one, to increase the Materia Tinctoria, and the other, to fix, if possible, those colors, we either have already, or shall hereafter discover for use. As to the first, Animals and Vegetables, besides other Natural Bodies, may abundantly furnish us. And in both these kinds some Colours are Apparent, as the various colours of Flowers, and the juices of fruits, &c. and the Senses of Animals: others are Latent, and discovered to us by the effects, the several Family's of Salt and other things may have upon them. Concerning the Apparent colors of Vegetables and Animals, and the various effects of different Salts in changing them from one colour to another; we have many Instances in M. Boyle. And if we might, with the good leave of that Honourable and Learned person, range them after our fashion, we should give you at least a new Prospect of them, and observe to you the conformity and agreement of the effects of Salt on the divers parts of Vegetables: Viz. 1. That Acid Salts advance the colours of Flowers and Berries, that is, according to the Experiments of M. Boyle, they make the infusions of Balanitium or Pomgranate-Flowers, Red roses, Clove-jilly flowers, Meferion, Pease-bloom, Violets, Cyanus Cyanus flowers, of a fairer red; also the juices of the Berries of Ligustrum, of black Cherry's, Buck-thorn-berries, of a much fairer red: and to the same purpose Acid Salts make no great alterations upon the white flowers of Jasmin and Snowdrops. 2. That Urinous Salts and Alcaly's, on the contrary, quite alter and change the Colours of the same flowers now named, and the juices of the said Berries also, from red to green; even Jasmin and Snow-drops. 3. Again, that in like manner Urinous Spirits and Alcaly's advance, at least do not quite spoyle the colors of the juices of leaves of Vegetables, of their Wood and Root. Thus M. Boyle tells us, that Urinous Spirits and Alcaly's make the yellow infusions of Madder roots red; of Brazil-wood, purplish; of Lignum Nephriticum, blew; the red infusion of Log-wood, purple; of the Leaves of Sena, red.4. That, on the contrary, Acid Salts quite alter and change the said infusions from red or blew, to yellow. In the next place we would note to you the effects of Salts upon Animals in the production and Change of colours; but the Instances are very few or none, that I meet with in any Author; the Purple-fish being quite out of use, and Cochineil and Kermes are by most questioned, whether they are Animals or no; but I think, we may confidently believe them both to be Insects, that is, Worms or Chrysalys's of respective Fly's in proxima fætura. We find then, and have tried concerning Cochineil (which of itself is red,) that upon the affusion of the Oyl of Vitriol, that is, an Acid Salt, it striks the most vivid crimson that can be imagined; and with Urinous Salts and Alcaly's, it will be again changed into an obscure color 'twixt a violet and a purple. Pliny somewhere tells us, that the Gan'ei in his time could dye with Vegetables, what the Romans with so much danger and pains sought for in the bottom of the Sea. Indeed, we find many Plants mentioned by the same Author, which either are not known to us at this present, or neglected. To what we have briefly observed out of Authors, we will subjoyne some of our own Considerations and Tryals And first, concerning the Apparent Colours in Flowers, we think we may insert: 1. That generally all Red, Blew and White flowers are immediately, upon the affusion of an Alcaly, changed into a Green colour, and then, in process of no long time, turned Yellow. 2. That all the parts of Vegetables, which are green, will will in like manner strike a Yellow with an Alcaly. 3. That what Flowers are already yellow, are not much changed, if at all, by an Alcaly or Urinous Spirit. 4. The Blew seed-husks of Glaetum Sylvestre old, gathered and dry, diluted with water, stain a Blew, which upon the affusion of Lye striks a Green, which Green or Blew being touched with the Oyl of Vitriol dyes a Purple; all these three colours stand. 5. On the tops of Fungus tubulosus, so called by M. Wray in his late Catalogue of the Plants of England, are certain red knots; these, upon the affusion of Lye, will strike a Purple, and stand. As for the Latent Colours in Vegetables and Animals; to be discovered to us by the affusion of Salts; they likewise, no doubt, are very many. We will set down only a few instances in both kinds, which have not been, that we know of, discovered or taken notice of by others. Latent Vegetable colours, 1. The Milky juice of Lactuca Sylvestris costata spinosa, and Sonchus asper & levis, upon the affusion of Lye, will strike a vivid flame-colour or Crimson, and after some time quite degenerate into a dirty yellow. 2. The Milk of Cataputia minor, upon the affusion of Lye, especially if it be drawn with a knife, and hath any time stood upon the blade of it, will strike a Purple or Blood-red colour, and by and by change into an ignoble yellow. Latent Animal dyes, 1. The common Hawthorn-Caterpillar will strike a Purple or Carnation with Lye, and stand. 2. The heads of Beetles and Pismires, &c. will with Lye strike the same Carnation-colour, and stand. 3. The Amber-coloured Scolopendra will give with lye a most beautiful and pleasant Azure or Amethystine, and stand. Lastly, we might consider the Fixing of colours for Use; but we are willing to leave this to more experienced persons; as also the Philosophizing on the particulars, we have produced, to better Heads. Some obvious Inferences we may venture to take notice of; 1. That in all the Instances above mentioned, whether Vegetable or Animal, there is not one colour truly fixed, however there may, I conceive, be some use made of them, as they are. I say, truly fixed, that is, proof of Salt and Fire; for, what seem to stand and be Lye-proof, are either wholly destroyed by a different Salt, or changed into a much different colour; which must needs prove a stain and blemish when it shall happen in the use of any of them. 2. That both the apparent apparent and latent colours of Vegetables are fixable: An instance whereof we may observe in the seed-husks of Glaustum, and the Use Diers make of the leaves after due preparation. 3. It is probable from the same instance, that we may learn from the colour of some part of the Fruit or Seed, what colour the Leaves of any Vegetable and the whole Plant might be made to yield for our use. 4. That the Latent colours of Vegetables are praexistent, and not produced; from the same instance of Woad, and likewise from this that the Milky juice of Lactuca Silvestris doth afford itself a Red Serum. 5. That the change of colours in Flowers is gradual and constant. 6. That the colours of Flowers, which will not stand with Lye, seem to be wholly destroyed by it, and irrecoverable: Thus it happens in the Experiment; that one part of a Violet-leaf, upon the affusion of Lye, is changed very soon into yellow, and will never be revived into a red by an Acid salt; but if another part of the same leaf be still green, it will be revived. 7. That the Dryness seems to be a means, if not of fixing, yet bringing the Vegetable colour into a condition of not wholly and suddainly perishing by the otherwise destroying Alcaly. 8. That those Plants or Animals that will strike different and yet vivid colours upon the affusion of different Salts, and stand, as the Cochinel and Glaustum, are probably of all others to be reckoned as the best Materials. It would have been a much safer way, to have put these Inferences in the fashion of Queri's; but besides that I affirm no more but matter of fact, it is lawful for our encouragement (as my Lord Bacon advises) to set up rests by the way, and refresh ourselves with looking back, though perhaps we have not much advanced. You will be pleased to excuse the little coherence that I have used in these notes, and attribute it to the readiness and affection I have to answer such inquiries as you put to me. I never yet did make this subject any part of my business, but the desire I have to search after and examine the Medicinal qualities of things in Nature, hath by the by presented me with such Phænomena, as I was not willing to leave unnoted, nor to refuse them you, though in a confused way, because you desire them. To conclude, how immethodical and barren these papers may seem; yet the consideration of them hath led me to a way of Fixing colours, which I willingly forbear to relate, until I may have an opportunity of shewing the Experiment before. fore the R. Society. I have found out a Colour most exquisitely black, & comparable to the best ink; even in the use of the pen, and which will not change by Fire or Salt. This an English Vegetable yielded me, and for ought I know (for I have not repeated the trial on any thing else) the like method will succeed to good purpose. I am, &c. An Accompt of some Books. I. Theodori Kerckringii M. D., ANTHROPOGENIE ICHNOGRAPHIA, sive Conformatio Fætus ab Ovo usque ad Ossificationis principia, in supplementum Osteogenie Fætum. Amstelodami, 1671. in 4°. After that this Author had the last year published, together with a Specilegium Anatomicum, his Osteogenia Fætum (both which were described No. 54. p. 1094. seqq. of these Tracts;) in the latter of which he had given an Accompt of the Formation of the Bones of an Humane Body, from the Second Month after Conception to the very time of the Infants Birth; he considered, that there were two things yet left behind, necessary to the perfect knowledge of Ossification; viz. First, what might be the Rudiments and Form of an Human Body, before it came to have any Firmness of Bones. Secondly, How after an Infants being born, the soft Bones acquire by little and little both their Hardness and Magnitude. Waving for the present the latter of these two, he undertaketh in these sheets (which are but three) to deliver the first Elements, as 'twere of our Body, from and even before the time of Conception; affirming. 1. Non tantum in nuptis & secundis Mulieribus, sed etiam in Virginibus esse non minus quam in Gallinis ova ponentibus etiam citra Galli consuetudinem, ova quædam * pisii viridis magnitudine, in quibus humor latet intus, qui, uti aliorum ovorum albumen & vitellus, dum coquitur, indurescit: Porro, ova illa mulierum, pelliculis extrinsecus circumdari, que postquam in uterum prolapsa sunt ova coitu fecundata, in Amnion & Chorion brevi commutentur; ova autem ipsa, duorum vel trium dierum spatio ad ceras nigri majoris magnitudinem excrescere. * Vide Nic. Stenonis Museuli Descriptionem Anatomicam editam A. 1667. & descriptam No. 32. Ubi in Narrationum ibi annuarum posteriori dictis Dr. Steno memorat, per digressionem, dari in Foeminis Testes ovario analogos. Ipse Author nostrae observat eiam, Fallopium jam tale quid notasse.