a considerable use in the striking of Colours, let me add to the many Experiments which may be afforded us to this purpose by the Dyers Trade, this Observation; That as far as we have hitherto try’d, those Liquors in general that are strong of Acid Salts have the Power of Destroying the Blewness of the Infusion of our Wood, and those Liquors indiscriminatly that abound with Sulphureous Salts, (under which I comprehend the Urinous and Volatile Salts of Animal Substances, and the Alcalisate or fixed Salts that are made by Incineration) have the vertue of Restoring it.

A Corollary of the Tenth Experiment.

That this Experiment, Pyrophilus, may be as well Usefull as Delightfull to You, I must mind You, Pyrophilus, that in the newly mention’d Observation, I have hinted to You a New and Easie way of Discovering in many Liquors (for I dare not say in all) whether it be an Acid or Sulphureous Salt, that is Predominant; and that such a Discovery is oftentimes of great Difficulty, and may frequently be of great Use, he that is not a Stranger to the various Properties and Effects of Salts, and of how great moment it is to be able to distinguish their Tribes, may readily conceive.  But to proceed to the way of trying other Liquors by an Infusion of our Wood, take it briefly thus.  Suppose I have a mind to try whether I conjecture aright, when I imagine that Allom, though it be plainly a Mixt Body, does abound rather with Acid than Sulphureous Salt.  To satisfie my self herein, I turn my back to the Light, and holding a small Vial full of the Tincture of Lignum Nephriticum, which look’d upon in that Position, appears Caeruleous, I drop into it a little of a strong Solution of Allom made in Fair Water, and finding upon the Affusion and shaking of this New liquor, that the Blewness formerly conspicuous in our Tincture does presently vanish, I am thereby incited to suppose, that the Salt Praedominant in Allom belongs to the Family of Sour Salts; but if on the other side I have a mind to examine whether or no I rightly conceive that Salt of Urine, or of Harts-horn is rather of a Saline Sulphureous (if I may so speak) than of an Acid Nature, I drop a little of the Saline Spirit of either into the Nephritick Tincture, and finding that the Caeruleous Colour is rather thereby Deepned than Destroy’d, I collect that the Salts, which constitute these Spirits, are rather Sulphureous than Acid.  And to satisfie my self yet farther in this particular, I take a small Vial of fresh Tincture, and placing both it and my self in reference to the Light as formerly, I drop into the Infusion just as much Distill’d Vinegar, or other Acid liquor as will serve to Deprive it of its Blewness (which a few drops, if the Sour Liquor be strong, and the Vial small will suffice to do) then without changing my Posture, I drop and shake into the same Vial a small proportion of Spirit of Hartshorn or Urine, and finding that upon this affusion, the Tincture immediately