An investigation of the silica deposits of southern Illinois . The time - temperature curves show that series 1 and series 2 are compar-able to about Cone 7. Beyond this temperature the series 2 test pieces receiveda greater heat treatment than series 1 test pieces, due to the longer time req-uired to reach the desired temperatures. This, of course, affects the specificgravities of the pieces, for the greater the heat treatment the greater theamount of inversion taking place. This is true for the inversions of silicafrom one form to another require energy.^ Hence in comparing series 1 and 2,be


An investigation of the silica deposits of southern Illinois . The time - temperature curves show that series 1 and series 2 are compar-able to about Cone 7. Beyond this temperature the series 2 test pieces receiveda greater heat treatment than series 1 test pieces, due to the longer time req-uired to reach the desired temperatures. This, of course, affects the specificgravities of the pieces, for the greater the heat treatment the greater theamount of inversion taking place. This is true for the inversions of silicafrom one form to another require energy.^ Hence in comparing series 1 and 2,beyond Cone 7, this must be considered. Series 1 :- In the series 1 bum the results are marked. Here it is evidentthat CaCl2 produces the greatest rate of inversion, followed by CaCl^ and MgCl2iCsiS04, CaO and MgO, in the order named, MgO producing the least effect. ThisThis holds true in all the three materials tested. This is true at the temper-ature of Cone 1, as the curves show, except in the case of CaSO^ and CaO whenused for bonds in the novaculite and g


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Keywords: ., bookcentury1900, bookdecade1920, booksubjectminesandmineralresou