Treatise on the falsifications of food, and the chemical means employed to detect them : containing water, flour, bread ... pepper, mustard / by John Mitchell.

  • Mitchell, John, analytical chemist.
Date:
1848
Catalogue details

Licence: Public Domain Mark

Credit: Treatise on the falsifications of food, and the chemical means employed to detect them : containing water, flour, bread ... pepper, mustard / by John Mitchell. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    removed, or the vessel get so thin as not to be enabled to withstand the pressure of the steam within, when the disastrous consequences, which generally follow the explosion of a steam-boiler, ensue. Dr. Clark, of Marischal College, Aberdeen, a short time since, patented a method for removing the carbonate of lime, river or spring-water contained, and which process is eminently successful, although I do not know whether it is generally in use. The following extracts, from a pamphlet published by him, will fully point out his method. To understand the nature of the process, it will be necessary to advert, in a general way, to a few well long-known chemical properties of the familiar substance—chalk; for chalk at once forms the bulk, as already mentioned, of the chemical impurity that the process will separate from water, and is the material whence the ingredient for effecting the separation will be obtained. In water, chalk is altogether, or almost, in- soluble ; but it may be rendered soluble by either of two processes of a very opposite kind. When burned, as in a kiln, chalk loses weight. If dry and pure, only nine ounces will remain out of a pound of sixteen ounces. These nine ounces will be soluble in water, but they will require not less than forty gallons for entire solution. Burnt chalk is called caustic