Pumice, potash

Potash in Pumice. In 1798 Dr. Robert Kennedy of Edinburgh demonstrated the presence of potash in pumice. He noticed that the pumice fused to a glassy enamel. Although Klaproth had found only silica, alumina, and iron, and had failed to detect potash in the specimen he... 

H. Erdmann s apparatus for preparing hydrogen chloride in a Kipp s apparatus is illustrated in Fig. 9. The middle bulb of the Kipp s apparatus contains pumice stone the upper and lower bulbs contain hydrochloric acid the upper end of Kipp s apparatus is closed by a rubber stopper fitted with a bulb containing potash lye. The separating funnel contains cone, sulphuric acid, and it leads to the inner bulb via a trap A containing sufficient mercury to cover the opening of the down-tube from the separatory funnel. Otherwise the diagram explains itself. A wash-bottle can be fitted to the exit tube B in the ordinary way. 

A powder which burns with a green flame is obtained by the addition of nitrate of baryta to chlorate of potash, nitrate of potash, acetate of copper. A white flame is made by the addition of sulfide of antimony, sulfide of arsenic, camphor. Red by the mixture of lampblack, coal, bone ash, mineral oxide of iron, nitrate of strontia, pumice stone, mica, oxide of cobalt. Blue with ivory, bismuth, alum, zinc, copper sulfate purified of its sea water [sic]. Yellow by amber, carbonate of soda, sulfate of soda, cinnabar. It is necessary in order to make the colors come out well to animate the combustion by adding chlorate of potash.15... 

Ten C.C. of the oil are heated for one hour on a sand-bath in an acetylation flask with twice its volume of formic acid (specific gravity, 1 226). It is advisable to add a few pieces of pumice to assist the boiling. The contents of the flask are cooled and 100 c.c. of water added, and the whole transferred to a separator. The acid layer is run off, and the oil is washed with water until the washings are neutral. It is then dried by means of anhydrous sodium sulphate and filtered. The formy-lated oil is then saponified with alcoholic potash in the usual manner, free acids being first neutralised, and the percentage of citronellol in the original oil calculated from the following formula —... 

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