Having made a Mass of a Pound and a half of Mercury, with half a Pound of Lead (the Chemists call such a Mass an Amalgama) I shook it in a Glass Vessel. There was produced a very black Powder. This I put into a Glass Cucurbite 14 Inches high; I pour’d pure distill’d Wine-Vinegar over it. By a gentle Distillation I took away the Phlegm. I then increased the Heat a little, but so that the Liquor did not boil. The Mercury ascended into the Head, together with the Phlegm, and thence into the Receiver. The same I tried and experienced other Ways. It is a Circumstance worthy a Chemist’s Speculation; but I shall say no more of it here. By much the like Artifice, I have seen Quicksilver made so volatile, that it was rais’d in my Digestory-Furnace with a less Degree of Heat, than that of a Man in Health, and ascended to the Sides of the Vessel. Do you think the Mercury was then purer? It was mix’d with Metal, and very dry. But perhaps I may some other time relate some very laborious Experiments which I have made for several Years, in examining Mercury and Metals, if I find that such Things are likely to meet with the Approbation of the Learned. EXPERIMENT XV. _GEBER has written, that pure Mercury is heavier than Gold: For a long time I endeavour’d to learn, Whether Mercury could be brought to a denser, and consequently a heavier State, than that it is naturally in? I began to attempt this by a Separation of the lighter and more changeable Part, from the more heavy Remainder, but cou’d not do it. I afterwards strove to defecate it by various Methods: It did not succeed. However, I discovered some Things that deserve the Contemplation of curious Observers, which I beg leave to mention, as follows: Two Ounces of pure Gold in a Mass, by hydrostatical Examination, in Rain-Water, defecated by gentle Distillation, I found to weigh in proportion to Water, as 19¹¹⁹⁄₅₀₀ to 1. Common Mercury, as sold, once distilled from the Retort to the same Water, weighs as 13⁵⁷⁄₁₀₀ to 1. Mercury amalgamated with purest Gold, and then distilled some hundred times, as 13⁵⁵⁄₁₀₀ to 1. Mercury so treated with the purest Silver, was to Water as 13⁵⁷⁄₁₀₀ to 1. Mercury united with Lead, and with it all turn’d into Powder, and thence resuscitated by a strong Fire, was to Water, as 13⁵⁸⁄₁₀₀ to 1. Mercury 511 times distilled, was as 14¹¹⁄₁₀₀ to 1._ These Statical Weighings were made by Instruments that cou’d not be found fault with, and with the most prudent Care. I spent some Years to prepare Mercury for this Purpose; and, for ought I know, no one else has had any Regard to it. Afterwards, many Things proper for Meditation may be drawn from thence, by proper Judges in this Matter: But I may be allowed to make a few Observations. COROLLARIES.