Notice respecting some Experiments on Alcohol. 1 33 



that time to pursue these experiments. They were resumed, 

 however, in the autumn ot 181 1. The second experiment 

 was repeated and varied, and solid masses of alcohol of 

 some magnitude obtained. Some of these I soldered to- 

 gether, using as a hot holt a rod of frozen mercury, and 

 sometimes a straw cooled down to a very low temperature. 



It now appeared to me to be an object of some impor- 

 tance to ascertain the form of the crystals which this sub- 

 stance assumes. This I found attended with some diffi- 

 culties which I did not anticipate, and attempts to over- 

 come them liave led to the discovery of some iacts which 

 I did not at all expect. 



The common masses exhibited crystals of different forms; 

 two kinds appeared to predominate, and each was tolerably 

 distinct in its kind ; but it was not very easy to perceive by 

 what increments or decrements the one could be supposed 

 to pass into the other: a rather casual circumstance, how- 

 ever, explained the source of this variety. — Attempting to 

 freeze alcohol by a modification of the gtneral process, 

 which I conjectured would yield more reirular crystals than 

 the common method, I observed that, before crystallizina;, 

 the alcohol separated into three very distinct strata ; the 

 uppermost was of a pale yellowish green, while the second 

 was of a very pale-yellow colour : — both these strata were 

 very thin, the last-mentioned was rather the thickest ; the 

 lowermost stratum was nearly transparent and colourless, 

 and very greatly exceeded the other two in quantity. After 

 allowing a part of the lower stratum, which I conceived to 

 be the pure alcohol, to freeze, I attempted to pour out 

 the remainder, but was prevented by the upper strata, which 

 proved to be solidified. The lowermost of these two strata 

 bore some marks of crystallization — the upj^er had none, 

 and proved so firm as to resist a straw with which I at- 

 tempted to perforate it to open a passage for the sublatent 

 liquid. On removing part yf these superior strata, and de- 

 canting the remaining fluid, the crystals of the lower stra- 

 tum appeared very distinctly to be rectangular jirisms of 

 equal planes, a few of them on one side ol the glass sur- 

 nir)unltd by {piadrangular pyramids, but most of them by 

 dihedral sununils. This experiment I repeated several limes, 

 and the results coincided. 



In order to ascertain whether these pltoenomena arose 

 fro^ji a decomposition of the alcohol, or from the separa- 

 tion ol foreign substanee<? previously held by it in solution, 

 the products of several of these ex|ieriment3 were mingled 

 together m a stoppered malrass; the whole was then raided 

 I 3 to 



