The Analyst Volume 1 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1876 Excerpt: ...of their duty to interfere with the sale of these. It is therefore all the more necessary that attention should be called to the question, in order that, if possible, moral influence as well as future legislation should be brought to bear upon it. Brass vessels for boiling fruit, in making preserves; and also "preserved meat " tins, the coating metal of which is partly composed of lead, have again and again been pointed out as examples of the articles referred to, but it is exclusively with enamelled cooking vessels that this communication has to do. The nature of "Enamel," or at least of the white, porcelainous kind most commonly met with on caBt iron cooking vessels, admits of great variety as regards the ingredients it contains, and their proportions, upon both of which the properties and character of the enamel depend. Thus, we may have poisonous ingredients, such as Lead or Arsenic, present in comparatively large quantity, without the risk of having even a trace of either of these metals imparted to any food cooked, provided sufficient silica has been employed in the composition to make a glass not readily acted upon by common salt, vegetable acids or other ordinary dietetic substances. But if, on the other hand, a deficiency of silica be used, the same proportions of lead and arsenic will give an enamel the use of which would be attended with great risk, on account of the easy action upon it of many of the substances employed in the preparation of food. That enamels, in practice, differ largely in composition as well as in properties, will be seen from the following analyses and experiments, which refer to three samples of white opaque enamel taken from three caBt iron cooking pots as sold for use, made by three different manufactu...