CONSIDERED LIGHTER THAN WATER. 391 



when the temperature of the water was steady, or followed its currents when its 

 temperature was disturbed. Further, it may be remarked, that when the preci- 

 pitated camphor is thrown into a large quantity of water, even at the temperature 

 40, part of it subsides to the bottom. That the whole does not subside is no more 

 than might be expected, considering that the smallest globule of air attached may 

 suffice to render a particle, or congeries of particles, buoyant. Examined with 

 the microscope, the particles that had subsided, or were suspended, appeared to 

 be quite homogeneous, of a globular form, or an approach to that form ; none of 

 them were crystallized. 



The specific gravity of unbleached wax, according to FABRONI, varies from 

 9600 to -9650, and of white wax from -8203 to -9662. Owing to the peculiar 

 properties of this substance either impervious or little pervious to air in its 

 solid state the rapid manner in which, when melted, on reduction of tempera- 

 ture it congeals at the surface, and its great degree of contraction on cooling 

 owing to these properties, the ascertaining of its specific gravity as a solid mass 

 is peculiarly difficult. 



In its liquid state, at the boiling temperature of water, I have found the spe- 

 cific gravity of yellow wax to be 0.856, distilled water of the same temperature 

 being considered as 1.000. This is the mean of two experiments; according 

 to one of which it was -854 ; according to the other, -858. At 100, its specific 

 gravity appeared to be to water of the same temperature as '952 ; and at 52, as 

 989. The specific gravity of white wax, at the boiling point of water, was found 

 to be '861 ; and at 50, it appeared to be -988. The manner of conducting the ex- 

 periments which gave these results was the following. The melted wax, in the 

 first instance, was poured into a bottle fitted for ascertaining the specific gravity 

 of liquids, immersed in boiling water, and the stopper heated was then introduced 

 into the bottle. Thus filled, the bottle weighed, of course gave the specific gra- 

 vity of wax at the boiling temperature of water its weight, filled with boiling 

 water, having been previously determined. For the lower temperatures, the 

 bottle, charged with melted wax, reduced as near to its congealing point as was 

 compatible with its liquidity, was immersed immediately after the introduc- 

 tion of the grooved stopper, into water purged of air by the air-pump, and then 

 allowed to cool previous to weighing. By this method I had hoped to exclude 

 air, and obtain satisfactory results. But the examination of the congealed wax 

 satisfied me that I was mistaken. On slicing the mass of wax, cavities were 

 found in its substance some of large size, containing water, others of small size, 

 many of them extremely small, requiring the aid of the microscope to be seen 

 distinctly apparently dry and empty it may be, they were filled with air. The 

 general appearance, I may remark, called forcibly to recollection the condition of 

 certain minerals and rocks, containing cavities, supposed to be formed during 



VOL. XV. PART III. 5 N 



