Inorganic chemistry / by Ira Remsen.

  • Remsen, Ira, 1846-1927
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: Inorganic chemistry / by Ira Remsen. Source: Wellcome Collection.

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    mand. Most of the rocks met, with are also quite com- plex, and it is difficult to isolate the constituents. If we look at a piece of coarse-grained granite, we see plainly enough that it contains different things mixed together, and if it be broken up we can pick out pieces of different substances from the mass. If we now examine a piece of each of the different substances thus picked out of the granite, it appears to be homogeneous, i.e. we cannot recognize the presence of more than one kind of thing in any one piece. If the piece is carefully selected it may be powdered finely in an agate mortar, and some of the powder examined with a microscope without the presence of more than one substance being recognized. We are able to isolate three substances from granite by simply breaking it up and picking out the pieces of different kinds. We might therefore conclude that granite con- sists of three substances. This is true, but it is not the whole truth. For it is possible by proper means to get simpler substances from each of the three already sep- arated. This is, however, a much more difficult process than the separation first accomplished. To effect the sep- aration of each of the three constituents of granite into its elements requires more powerful means. Substances must be brought in contact with them which act upon them, changing their composition, i.e. act chemically upon them, and high heat must be used to aid the action. By skilful work it is possible to separate the three com- ponents of granite into their elements. From the above it is evident that substances may be united in different ways. They may be so united that it is a simple thing to separate them by mechanical processes. Or they may be so united that it is impossible to separate them by mechanical processes. By a mechanical process is meant any process which does not involve the use of heat, electricity, or chemical change. Thus, the mechan- ical process made use of in the case of granite consisted in picking out the pieces. The separation of the parti- cles of different sizes by means of a sieve is a mechanical process. The separation of two liquids which do not mix with each other is a mechanical process. Complex sub-