'84- ON THE SUPPOSED CURRENTS IN HOT LIQUIDS. 



without carrying any of the blue infufion along with them. 

 On trial the bo- I accordingly lighted a lamp, and put it at fome diftance 



cuUtefthrough" below the veffeI A > P Iacin g the ve(TeI exaaiy between my 

 both fluids with- eye and the window. The lamp was at fuch a diftance, that 

 out any indica- j t was f ome t j me \y,{ OTe the floating bodies began to move, 

 tion or a cur- 

 rcntj Atlaft, however, they afcended gradually, palled the plane 



<m, and entered the colourlefs medium, without being accom- 

 panied by any of the blue infufion. They then defcended again 

 in the ufual manner ; and this alternate motion continued for 

 fome time, without occaiioning a mixture of the two liquids. 

 Thus I obtained a full demonftration that the motion of the 

 floating bodies was not occafioned by currents in the liquid, 

 but was altogether independent of any fuch currents. Every 

 time that a floating body paffed the line m, the blue infufion 

 was agitated, and its furface raifed into a wave. By the 

 conftant repetition of this undulation, the plane m became ill- 

 defined, and gradually afcended higher and higher, till at lair, 

 and ten minutes almoft the whole of the water acquired a blue tinge. But it 

 elapsed before the was a i mo ft ten minutes before this happened, and the motion 

 motion had car- „... . . ... . - v ; *• • 



ried the blue OI the floating particles, which continued without interruption 



tinge through during the whole time, was altogether unequivocal. 

 Experiment 1 *; * ** was ^^ neceflary to repeat the experiment with the 

 An alkaline fo- amber itfelf, in order to afcertain whether or not its motions 



ution, wrt W ere of the fame nature with that of the floating bodies in 

 floating grains of © 



amber, was the laft experiment. I therefore filled the glafs veffel A, to 

 boiled, and left t.n e height n, with an alkaline folution containing amber 

 The upper part, floating in it. I then heated the folution boiling hot by hold- 

 to the depth of i n g the veffel over a fire, and even allowed it to boil for fome 

 the/dnged.' N*o tmie « The veiTel was then fufpended in a room, where the 

 change whatever temperature of the air was 50°, and the alkaline folution al- 

 took place in the lowed tQ cool down to 150 o # * j t hen tinged the furface 

 tinged fluid, ° 



though the am- of the folution by means of a drop or two of the infufion of red 

 ber circulated ca bbage, fo as to form a coloured ftratum of about half an 

 whole flu'd, inch thick at the furface of the folution. f The cooling con- 

 while cooling, tinued without interruption, and the liquid reached the tem- 

 perature of the air without the fmalleft alteration in the 

 coloured ftratum, or any mixture of it with the colourlefs 



* By previous trials I had afcertained that at a higher temperature 

 the experiment does not fucceed. 



f The colour thus communicated is yellow when only a little 

 -*r v i cabbage juice is ufed ; too much gives a green colour. 



folution 



