ON THE EFFECTS OF HEAT. 103 



abovit upon the surface of the solution. They did not ap- 

 pear to be of a gaseous, but of a liquid nature: they were 

 lexceedingly spherical, and their specific gravity so small, 

 that they scarcely sunk at all into the liquid. The bubbles 

 of steam, which were abundant, always receded from them; 

 so as to leave a considerable space around them in every di- 

 rection. Dr. Higgins observed a similar phenomenon, du- A similar 

 ring the distillation of a mixture of sulphuric and acetous ob!e"rverb"" 

 acid. I will give the description and explanation of it, in Dr. Higgins. 

 his own words. — " When the quantity of acetous acid 

 *' amounted to about three ounces, and rose in the receiver 

 " so high, that the distance between its surilice and the 

 ** nozle of the long slender neck of the retort did hot 

 *' exceed a quarter of an inch, and when the drops fell at 

 ** the interval of three or four seconds, each of them, re- 

 " bounding after the fall, and still preserving the globular 

 *' form, rolled on the acid liquor; and then, after fioating 

 ** in a quiescent state for five or six seconds, burst snd- 

 *' denly, and spread upon it. Some of these globules in 

 ** their motion struck the preceding ones, and frequently 

 *' the motion was communicated without either of them 

 *' bursting for "some seconds after they became quiescent. 

 ** Afterward, when the acid in the receiver rose, and was 

 ♦• not distant from the nozle of the retort by more than the 

 ** diameter of a large drop, the liquor, which trickled down, 

 ** did not discharge itself into the acid, either in the fove- 

 *• going maner, or in that of a column ; but it formed glo- 

 *' bules of six times the former bulk, each of which, pre- 

 •' serving its proper form, sunk by half its diameter into 

 " the acid liquor, without mixing with it; but when the 

 •* size of any globule increased so as to exceed ^Vof an 

 ** inch in diameter, it then parted from the nozle, and 

 ♦' spread on the liquor. All this looked as if each drop car- 

 *' ried its proper atmosphere of repellent matter, which it 

 " retained for a considerable time, with a force greatly su- 

 •• perior to the weight of a grain, for the drop could not, 

 *« by reason of its mere aggregation, rebound from liquor 

 ** of the same kind, and roll on it, and dip ar»d swell in it 

 *' without mixing." Dr. Higgins could not produce the 

 same appearance, in the distillation of water, or of spirit of 

 wine. I will 



