Easy lessons in chemistry, organic and inorganic

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1884 edition. Excerpt: ... chloride, because free from water, was produced, which is blue in colour. Cobalt acts like nickel with amnionic sulphide and hydrochloric acid; but we can always recognise it by placing a little along with some borax in a loop formed at the end of a piece of platinum wire, and then exposing them to an ordinary gas flame, made very much hotter by means of a blow-pipe, so that the borax and cobalt shall melt in the flame. It will be found that a bead of blue glass will have been produced. The illustrations will best explain the blow-pipe, and how it is used. Zinc–Symbol, Zn; atomic weight, 65. This is a metal whose usefulness has increased enormously during the last fifty years. The ores from which it is extracted are principally blende, in which zinc is joined to sulphur (ZnS); calamine, in which it is joined to carbonic acid (ZnC08); and red zinc ore, in which it is joined to oxygen, and mixed with a little manganese oxide, which gives it the red colour. The first and second of these ores are very generally distributed throughout Europe, the last is found extensively in the United States of America. The process of separating zinc from the ore is first to convert the ore into oxide by roasting, and then subject the oxide to great heat in presence of carbon or charcoal, by which the zinc is made to leave the oxygen, and distil over like sulphur. In commerce, zinc is very frequently called spelter. We have already seen that it forms many alloys, such as brass, bronze, German silver, etc., but as it is rather hard and brittle it was formerly little used alone. Of late years, however, it has been found that if it be heated to between 250 and 300 F., it becomes so soft that it can be rolled out or hammered into sheets-and as lead has become...