in Fluids. 385 



horizontal Currents were produced by Heat. Conjectures 

 respecting the proximate Causes of the Winds. 



THOUGH this Essay is already grown to a much 

 larger size than I originally intended, and even 

 larger than I could have wished (well knowing how 

 great an evil a great book is generally thought to be), 

 I could not bring it to a conclusion without adding 

 one Chapter more. In this Chapter the reader will find 

 accounts of several experiments, some of which he will 

 probably consider as not altogether uninteresting. To 

 take up as little of his time as possible, I shall be very 

 brief in these accounts, and in general shall leave the 

 reader to draw his own conclusions from the results of 

 the experiments I shall describe. 



I . An Account of several simple Experiments^ which show 

 that Heat does not descend in Fluids. 



If a thermometer constructed with a long and narrow, 



D * 



naked cylindrical bulb (6 inches long, for instance, and 

 \ an inch in diameter), and filled with mercury, oil, spir- 

 its of wine, or any other Fluid proper for that purpose, 

 with which it is required to make the experiment in 

 question, such thermometer being at the temperature 

 of the air in summer, or at any temperature above the 

 point of freezing water, if the lower end, or half, of its 

 bulb be plunged into a glass tumbler filled quite full to 

 the brim with pounded ice and water, the height of the 

 Fluid in the tube of the instrument will show that half 

 the Fluid in the cylindrical bulb of the instrument is 

 ice-cold, while the temperature of the other half of it 

 remains unchanged. 



VOL. I. 25 



