Experiments upon magnesia alba, quicklime, and some other alcaline substances.

  • Black, J.
Date:
1910
Catalogue details

Licence: In copyright

Credit: Experiments upon magnesia alba, quicklime, and some other alcaline substances. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

    18/56 (page 14)
    was intirely insipid, and agreed in every chemical trial with pure water. The powder, after being perfectly well dried, weighed thirty seven grains. It did not dissolve intirely in spirit of vitriol; but, after a brisk effervescence part of it subsided in the same manner as the calcarious earths, when mixed with this acid. When I first tried this experiment, I was at the trouble of digesting the mixture in the heat of boiling water, and did not then know that it would succeed in the heat of the air. But Dr. Alston, who has obliged the world with many curious and useful discoveries on the subject of quick-lime, having had occasion to repeat it, I learned from him that heat is not necessary; and he has moreover added an useful purpose to which this property of magnesia may be applied; I mean the sweetening of water at sea, with which lime may have been mixed to prevent its putrefaction. That part of the dried powder which does not dissolve in spirit of vitriol, consists of the lime separated from the water. Quick-lime itself is also rendered mild by magnesia, if these two are well rubbed together and infused with a small quantity of water. By the following experiments, I proposed to know whether this substance could be reduced to a quick-lime. An ounce of magnesia was exposed in a crucible for about an hour to such a heat as is sufficient to melt copper. When taken out, it weighed three drams and one scruple, or had lost T\ of its former weight. I repeated, with the magnesia prepared in this manner, most of those experiments I had already made upon it before calcination, and the result was as follows. It dissolves in all the acids, and with these composes salts exactly similar to those described in the first set of experiments : but what is particularly to be remarked,