On Chemical Solution. Congelation. iSj 



. A cylindrical glafs jar 4| inches in diameter, and 7A inches high, was placed in the middle 

 ^another cyliaJrical glafs jar 7? inches in diameter, and eight inches hig.h, which flood in a 

 {hallow earthen dilh, nearly filled with pounded ice and water. This apparatus was placed 

 in an uninhal'ited room, where the temperature was conftantly at about 36 degrees of Fahren- 

 heit. In this fituation, a quantity of pure ice-cold water, flightly tinged with turnfoi, was 

 poured into the inner jar, to the height of more than two inches; and then by means of a 

 glafs funnel, which ended in a long narrow tube, by introducing this tube into the frefh 

 water, and refting it on the bottom of the jar, a quantity of the ftrongeft clear ice-cold brine 

 of common fait, equal to that of the frefh water, was poured very flowiy in. The ditFerenoc 

 of colour rendered the two fluids very diftinguifliable, and fhev^ed that they were nordif- 

 pofed to mix together. 



The ipace between the two jars was then filled with large fragments of ice and ice-cold 

 water, btcaufe pounded ice would have obftruiled the vi$w; and wliea this was done, the 

 tinged water of the interior jar was carefully covered with ice-cold olive oil to the height of 

 about an inch. This laft fluid ferved to prevent the water from being agitated by the air^ 

 or cooled by evaporation or the communication of heat. 



The fluids remained in perfect tranquillity, without the fmalleft difpofition to mix together, 

 during four days. At the end of that time the fmalleft jar was removed without agitation, 

 and placed in the window of a room heated by a German ftove. In lefs than an hour it was 

 perceived that the brine and the tinged frefh water began to mix, and at the end of 24 hours 

 they were intimately mixed throughout. 



The author leaves philofophers to deduce their own concluftons from this experiment; 

 but in the mean time points out a refult, which is not only curious in itfelf but capable of 

 affording important confequences. He thinks there arc ftrong reafons to conclude, that 

 were a lake but very deep, its waters near the furface would necefliirily be frelb, even though 

 its bottom fhould be one folid mafs of rock-falt. He fuggefts the advantage which might 

 accrue to an inland country where fait is fcarce, if on experiment it ftiould be found that the 

 water at the bottom of fome deep lakes is fait. And. that the water at the bottom of all very 

 deep lakes ought neceflarily to be fait, even in fituations where no mines of fait exift, ap- 

 pears to him probable, from the geological fadls which indicate that moft of our continents 

 have been covered by the waters of the ocean. If ever that event happened, he thinks it 

 highly probable, that the fait water left at the bottoms of all deep lakes by the fea, on its 

 retiring, muft be there now. 



Chai'. II. In the former part of this EflTay, the author has availed himfelf of all the cir» 

 cumllances which accompany the cooling and congelation of water, to account for the 

 ftriking efFe£ls which they produce in the economy of heat on the furface of the globe. As 

 water contra£ls by cooling to the 41ft degree, and afterwards expands until it afl\imes the 

 folid ilate ; it fliould feem at firfl confideration, that, when the heat is abflrrailed from the 

 bottom of a veffel containing this fluid, the particles of water would rife and elude the re- 

 frigerating power until the whole mafs was cooled to that temperature, and afterwards con- 

 tinue to circulate in the fame manner as if the temperature were aftually rifing, until at 

 length the whole mafs having arrived at the temperature of 32°, it would become folid almpfl: 

 infta'ntaneoufly. But thefe inferences fuppofe the particles to circulate with lefs impediment 

 from inertia and refiftance than would be fufScient to detain them long enough at the lower 



. Y a furface 



