[6] The Marquis de Montalembert, in a Memoir read before the Academy of Sciences, proposes a new method of effecting these evaporations, together with some considerable improvements in the structure and disposition of the buildings necessary for that purpose. They are called by the French Batiments de Graduation; which may properly enough be rendered Brine-houses.
[7] See the Table of Affinities, Column IV.
[8] M. Réaumur hath obliged the public with a treatise on the means of converting Iron into Steel, in which he hath exhausted the subject. Such as desire the amplest and most useful instructions on that part of metallurgy, would do well to consult his Work.
[9] See the Memoirs of the Academy for 1730.
[10] See the Memoir given in by me on this subject to the Academy of Sciences in the Memoires l'Acadamie 1754.
[11] I believe this proposition is not strictly true: for it appears to me, that, in order to make the heat, produced by the simultaneous frictions of an hundred particles, an hundred times more active than that produced by the successive frictions of the same number of particles, it is necessary that the simultaneous frictions should act all together in one point or center; which is impossible. But, as the particles that rub against each other, in the present case, are very near and contiguous, it is still true that the heat, resulting from their simultaneous frictions, is much more active than that produced by successive frictions only: which is sufficient for our present purpose.
[12] These white vapours do not appear when the vessels are perfectly close. Mr. Hellot, to whom we owe the remark, having performed this operation in a crystal retort procured from London, the neck of which had been rubbed with emery in the mouth of its receiver, so that these two vessels fitted each other exactly, saw the ætherial liquor distil pretty fast, but without white vapours. He then loosened the receiver, by turning it a little upon the neck of the retort, so that the external air might get in; whereupon the white vapours appeared immediately. When the receiver was close fitted on again, the vapours disappeared. He repeated the same thing five times from half hour to half hour, and these vapours as often appeared and disappeared.
[13] Mr. Eadows, in a little English book, entitled The Modern Apothecary.
[14] It could not be any longer concealed; for M. Geoffroy having made some experiments on the same subject, without knowing any thing of what M. Boulduc had done, likewise discovered it. See the History of the Academy for 1731, p. 35.
[15] Memoirs of the Academy for 1734, p. 421.