Conversations on chemistry : in which the elements of that science are familiarly explained and illustrated by experiments and plates : to which are added, some late discoveries on the subject of the fixed alkalies / by H. Davy ... ; a description and plate of the pneumatic cistern of Yale College, and a short account of artificial mineral waters in the United States ; with an appendix, consisting of treatises on dyeing, tanning and currying.

  • Marcet, Mrs. (Jane Haldimand), 1769-1858.
Date:
1813
Catalogue details

Licence: Public Domain Mark

Credit: Conversations on chemistry : in which the elements of that science are familiarly explained and illustrated by experiments and plates : to which are added, some late discoveries on the subject of the fixed alkalies / by H. Davy ... ; a description and plate of the pneumatic cistern of Yale College, and a short account of artificial mineral waters in the United States ; with an appendix, consisting of treatises on dyeing, tanning and currying. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    Emily. But have not all liquids the same solvent pow- ' er as water ? Mrs. B. The solvent power of other liquids varies accord.ng to their nature, and that of the substance submitted to their action. Most of these solvents, in- deed ditfer essentially from water, as they do not merely separate the intregrant particles of the bodies, which they dissolve, but attack their constituent princi- ples by the power of chemical attraction, thus produ- cing a true decomposition These more complicated operations, which may be distinguished by the name of chemical solutions, we must consider in another place, and confine our attention at present to the simple solu- tions by water and caloric. Caroline. But there are a variety of substances which, when dissolved in water, make it thick and muddy, and destroy its transparency. Mrs. B. In this case it is not a solution, but simply a mixture. I shall show you the difference between a solution and a mixture, by putting some common salt into one glass of water, and some powder of chalk into mother ; both these substances are white, but their ef- fect on the water will be very different. Caroline. Very different indeed ! the salt entirely disappears and leaves the water transparent, whilst the chalk changes it into an opake liquid like milk. ^ Entity. And would lumps of chalk and salt pro similar effects on water ? r]uoe Mrs. B. Yes, but not so rapidly ; salt is indeed soon melted though in a lump, but chalk which does not mix so readily with water, would require a much greater length of time ; I therefore preferred showing you the experiment with both substances reduced to powder, which does not in any respect alter their na- ture, but fecilitates the operation merely by presenting a greater quantity of surface to the water. I must not forget to mention a very curious circum- stance respecting solutions, which is, that a fluid is not increased in bulk by holding a body in solution. Caroline. That seems impossible ; for two bodies cannot exist together in the same space.