MAKING BRICKS WITH STRAW.

Stratford Evening Post, Volume XXXV, Issue 75, 5 April 1913, Page 3

MAKING BRICKS WITH STRAW.

an EGYPTIAN SECRET DISCOVERED. Why did the Israelites, while working under the Egyptians, use straw in the manufacture of bricks? it is usually stated that the straw was used as a mechanically binding agent, but in this case why did not the Egyptians use hair or some one of many other available fibres which would have been much better binders than straw? Also, why did the Israelites, when they could no longer get straw, resort to stubble and find u answer their purpose? (See Exodus, chap to These questions are answered effectively by Edward G. Acheson, SC.D., who, in a paper read before the Society of Chemical Industry, relates his experiments and discoveries on the effect of certain vegetable infusions on the binding powers of clay and graphite. By rare good fortune the writers language is as lucid and unburdened as Ids own solutions, so that there is no difficulty in understanding what ho means. As a manufacturer of artificial graphite from coal, he wished to find the best kind of clay for binding this material so as to make crucibles. He found that European clays were better than American for this purpose. Seeking to find the reason, he failed to find it by chemical analysis and therefore resorted to books. The books told him that sedimentary clays were more plastic than residual clajs. From this he inferred that sedimentary clays must have gathered some-, thing during the course of their journey to their final resting place. What was this something? Probably vegetable matter. So the experimenter tried the effect of vegetable infusions on clay, using in his early experiments tanning with kaolin. The result was as desired; the clay became much more plastic. Searching literature for some mention of the subject, he could find only the above mentioned Biblican reference. Then he determined to try straw, although it contains no tannin; and the result was the same. The action is as follows: the vegetable solution prevents the particles of clay, graphite, etc., suspended in the water, from coagulating into larger masses—“flocculating” as the term is. It deflocculates the clay. Hence the particles remain go minute that they form a colloidal solution, and the resulting material, after the water has. been removed, it is not friable, but plastic and landing, owing to the smallness <pf its particles. Some tof his, diffusions of graphite in water have stood for rno.ie than two years without showing signs of settling. Such diffusions p,n being submitted to an expert with the ultramicroscope, were declared to bo of the kind known as colloidal, where the particles were exceedingly minute and in constant motion. Many other materials, both m suspended matter and in vegetable extracts, were tried and found successful.

This certainly throws an interesting light on the passage from Exodus, and it Is difficult to resist the conclusion that the writer has found its, true meaning. There can ho no reasonable reply to the contention that ancient civilisations, so richly endowed with capabilities as the Egyptians, must have known of a good many processes and methods of which we are nob aware.