376 REIBLING AND REYES. 



were produced from slaked lime and not from calcium oxide as lie stated. 

 White emphasizes the time factor which enters into the reaction. The 

 time required for the formation of these crystals depends primarily upon 

 the amount of water which is available at all stages of their development. 

 We found that on increasing the percentage of water in the test solution, 

 the crystals formed more and more quickly and finally, 9 drops of water 

 in 30 cubic centimeters of the solution produced them almost immediately. 



Another habit of formation of calcium hydroxide phenol crystals 

 remains to be considered. White states that "the crystals formed from 

 lime which has been fused in the electric arc * * * appear as plumes 

 or feathery petals which in favorable cases give the group somewhat the 

 appearance of a chrysanthemum." 21 However, the development of plume- 

 shaped groups of crystals does not necessarily indicate fused limed. 



Lime melts at an extremely high temperature; so high, in fact, that 

 Arthur L. Day and E. S. Shepherd 22 found it impossible to make a 

 satisfactory determination of its melting point. They state that "lime 

 can be fused in the electric arc under favorable conditions." We were 

 unable to prepare homogeneous, fused lime in the electric arc of the ap- 

 paratus at our disposal, but the sintered mass which we obtained produced 

 plume-like aggregates of crystals in abundance when treated with White's 

 reagent. Similar forms were also secured by us from pure marble which 

 had been heated in a porcelain crucible on the forge and from under- 

 burned Portland cement clinker the temperature of burning of which was 

 known to be much too low to admit the possibility of the presence of fused 

 lime. 



White also found plume-shaped crystals in Portland cement 23 burned 

 by E. D. Campbell at a temperature below 1,500 degrees. 



We are inclined to question the presence of fused, free lime even in well- 

 burned Portland cement clinker. The highest temperature of burning 

 is seldom above 1,700 degrees and in the rotary process especially, it is 

 not probable that the free lime would absorb enough heat units in a 

 sufficiently short time to cause it to melt, except perhaps at local, very 

 minute points, if the effect were similar to that found in the mantle of a 

 Welsbach burner. 



However, since it has been found impossible to produce plume-shaped 

 crystals from lime which has only been heated in the ordinary blast lamp, 

 it is evident that it must at least be sintered before the habit of the 

 crystals under consideration can be observed after the addition of phenol 

 and water. 



The reason for the formation of crystals in plume-shaped aggregates 

 becomes evident by a study of the method of their formation. 



21 Loc. tit. 



22 Joum. Am. Chem. 8oc. (1909), 28, 1089. 



a Loc. tit. (figure 3). 



