Authentic Science Fiction Monthly No. 42 — page 147: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

AUTHENTIC SCIENCE FICTION These are the results you may obtain: SUBSTANCE OUTER INNER FLAME FLAME Copper Blue or Colourless green or red Iron Yellow or Bottle green brown Chromium Emerald Emerald green green Manganese Amethyst Colourless Cobalt Deep blue Deep blue Nickel Brown Grey or black These are the simplest and best preliminary tests. In a future article we will deal with the systematic detection of the elements, but before ending this section we should consider one of the most important principles of analysis, and that is precipitation. Under some circumstances, when water solutions of two substances are mixed, a solid separates out. This operation is called precipita- tion. As an example, let us take a weak solution of silver nitrate and a weak solution of sodium chloride. When these two are mixed, a white precipitate of silver chloride forms. Thus, by adding sodium chloride solution to a test solution we can tell if silver is present, and by adding silver nitrate solution to a test solution we can tell if a chloride is present, 146 By means of the apparatus shown in the first diagram, the precipitate can be separated from the filtrate, and we can carry out further tests on the latter to see if anything further is present. The stand is made of wood and should take but a few minutes to construct. In the top flange a hole is cut to accommodate a glass filter funnel, the stem of which juts into, and holds upright, a test tube beneath. The filter paper can be bought as such, or blotting paper (white and clean) may be used. Another example of precipitation uses a solution of barium chloride. This precipitates sulphates as barium sulphate, afd conversely a solution of sulphate will show whether barium is present. Here is a hint to keep you going until next month. There is enough information in this article to enable you to analyse table salt, glauber salt, blue vitriol, green vitriol, sal ammoniac and plaster of paris. Remember to do each test on a separate portion of the test sub- stance and, when working with plaster of paris, boil a very small quantity of it with a fair amount of water to get a solution. Next month we will give you the chemical constituents of these substances, and will go on to deal with the “wet tests.” conmicbooks.con)