PERIODIC PRECIPITATION OF FERROUS CARBONATE R. J. HARTMAN, E. W. JiANNING,
AND
F. J. GALLION
Deparliucnl oJ CtlenzistrU, Indiana Universilu, Bloomington, Indiana
Received August 82, 1932 INTRODUCTION
In a previous article of This Journal, “The Liesegang Phenomenon Applied to the Lake Superior Iron Formations” (l),a synthetic demonstration of the Lake Superior iron formation is presented. Silica gels were prepared by mixing ammonium carbonate and sodium silicate solutions. Over these gels were placed solutions of ferrous ammonium sulfate of various strengths. There resulted in the gel bands of ferrous carbonate. In the text of this article is cited the fact that the same banded structure might occur if a silica gel prepared from carbon dioxide and sodium silicate solution were employed. Also, it is proposed that with this gel ferrous sulfate might yield bands as good as those obtained with ferrous ammonium sulfate. It is the purpose of this investigation to study further the periodic precipitation of ferrous carbonate in different gels, thus substantiating the theory of formation of the Lake Superior iron formations proposed in the previous article. The facts cited in this paper as well as those of the former article tend to support the geologic theories proposed by C. R. Van Hise and C. I
