Inorganic chemistry, theoretical and practical : a manual for students in advanced classes / by William Jago.

  • William Jago
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: Inorganic chemistry, theoretical and practical : a manual for students in advanced classes / by William Jago. Source: Wellcome Collection.

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

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    nected at the lower ends by a piece of fine platinum wire. Around this wire a piece of gun-cotton, weighing about lo or 12 grains, is lightly wrapped, and then introduced into the flask. By means of an air-pump the flask is completely ex- hausted and then weighed. On passing an electric current through a, b, the platinum wire be- comes red-hot and ignites the gun- cotton, which completely disappears, with a bright flash. On again weigh- ing the flask it will be found to re- main unaltered in weight. As a result of being heated the gun- cotton has undergone a chemical change by which it has been con- verted into gases ; these, however, weigh precisely the same as did the original gun-cotton. The result of this and all other similar experi- ments is summarised in the state- ment that matter is indestruc- tible, and consequently the same weight of material remains after any and every chemical change as there ■was before its commencement. 6. Mechanical Mixture and Chemical Combina- tion.—It is important to learn to distinguish between these two different processes, and this end is best attained by the study of a typical experiment. If some sulphur be obtained in the form of a fine powder it is of a briUiant yellow colour, while copper reduced to the state of filings is of a red tint. In general properties the sulphur is extremely brittle, while the copper is marked by great toughness. These two powders may be mixed together in any proportion, with the production of a greenish-yellow mass, the yellow being more or less pro- nounced according to the quantity of sulphur present. If the copper and sulphur be in a sufficiently fine state of powder the mixture shows to the naked eye no signs of the presence of individual particles of either sulphur or copper ; still, under a
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