A dissertation on quick-lime and lime-water ... / [Charles Alston].

  • Charles Alston
Date:
1752
Catalogue details

Licence: Public Domain Mark

Credit: A dissertation on quick-lime and lime-water ... / [Charles Alston]. Source: Wellcome Collection.

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    repeated this feven times, the laft Water was not quite free of the Lime. So even excluding the eighth and laft three Gills, I had more than feventy-feven Ounces of Lime-water from fixty-nine Grains of this Chalk Quick-lime; that is, about live hundred and forty times its own Weight. And the remaining Lime with the Crufts well dried, weighed fixty-live Grains, as if there had been but one Grain of the Quick-lime in nineteen - Ounces of Lime-water. This muft at firft Sight appear altogether inconfiftent with Truth, Lime-water certain¬ ly containing a much greater Proportion of the Lime in it. For 11. Lime-water, however well filtered, expofed to the Air, in lefs than a Minute’s Time throws up on its Surface a Scum, which foon becomes a thin Pellicle, tranfparent at firft, but in a Night’s Time or fo, a white, opake, and very brittle Cruft, thickening but lit¬ tle afterwards, and never fubfiding, unlefs it be broken. If this Cruft be taken off, another will gather, fo long as there is any Lime in the Water. For when none ap¬ pears, the Water has no other Efte£l on Syrup of Vio¬ lets than common Water: And as the Crufts gather, the Water becomes weaker. So long therefore as that of which thefe Crufts are, at leaft in Part, formed, con¬ tinues diftblved in the Water, *the Lime-water retains its Qiialities, or continues Lime-water, and no longer j although the fame Crufts, when formed, have nothing of the Nature of Quick-lime in them j which may be reckoned a fourth Paradox. Now, 12. To find how much of thefe Crufts Lime-water contains, or can afford, any certain Qiiantity of it needs only ftand a few Days in an open wide-mouthed Veffel, now and then ftirring the Water, and breaking the Crufts, until the Water make no Change of the Co¬ lour of Syrup of Violets; then filtering the Liquor, and drying the Crufts. I'hus by many repeated Trials on common. Shell, and Chalk Lime-waters, I found (a), that I four Gills, or fourteen Ounces fix Drams and twenty-four t Grains of any of them, gave of cal^arious Crufts eleven i or eleven and a half Grains j that (b) the firft Infufion did
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