On a singular instance of Crystallization. 129 



the pyramid ; often grouped, crossing each other at various angles, 

 and then exhibiting both terminations ; white, transparent, possessing 

 a vitreous lustre, brittle, the fracture disclosing a regular internal ar- 

 rangement ; the odor, like that of the oil at the same temperature, 

 was slightly fragrant. When detached from the sides of the vessel, 

 they instantly subsided in the water. The temperature of the air 

 being about 62° Fah., the crystals partially exposed above the water, 

 were slowly diminishing in size and resuming a solid form, on those 

 below, which were at 45° Fah. ; the difference of temperature be- 

 ing maintained by the evaporation of the oil from the surface of the 

 fluid, contained in an imperfectly conducting vessel. When with- 

 drawn from the water, and wiped, they soon melted into a colorless 

 fluid ; in size, they varied from one and a half inches in length, by 

 half an inch in width, to one-tenth these dimensions. 



Haying often observed the oil of sassafras, inclosed in glass phials, 

 perfectly fluid, at all the intermediate degrees of temperature from 

 • — 10° to -\-70° Fah., it seemed to me probable that a crystallizable 

 compound had been produced by some alteration in the constituents 

 of the oil. With this supposition in view, I carefully removed the ad- 

 hering water from some fine crystals, by means of bibulous paper, 

 and allowed them to melt in a clean, covered vessel. Portions of 

 the resulting fluid, in suitable vessels, were cooled to different ther- 

 momeiric points, under circumstances deemed favorable to ordinary 

 crystallization ; the oil remained fluid, although its mobility dimin- 

 ished by reducing the temperature ; yet no tendency to assume a 

 solid form was indicated. 



On examination, the fluid obtained from the crystals presented the 

 physical and chemical properties of pure oil of sassafras, so far as I 

 know them ; precautions were taken to remove water if mixed with 

 it, but the desiccating compounds were not moistened, nor could it 

 be resolved into two fluids by distillation. 



Recurring to the circumstances under which the crystals were first 

 observed, a portion of the oil was placed, with three parts of water, 

 in a cylindrical glass vessel, the vessel, immersed in a freezing mix- 

 ture, was occasionally agitated, until the whole was reduced to a soft 

 solid mass; crystals of the oil were now observed, and by allowing 

 the vessel to remain in a warm room, the congealed water became 

 fluid, leaving the crystals incrusting the sides and bottom of the ves- 

 sel. The crystals thus obtained, presented varieties of the same 

 form as the original crystals from which thev were derived, and in 



Vol. XX.—No. 1. 17 



