234^ MAXIMUM DENSITY OP WATER. 



With the hot J" ^^e experiments in queftion, (with the hot ball) fome of 

 conefomeof the particles of the water, namely, thofe which came Hrft into 



the fluid afcend- , a. • i ^t • i .... 



ed and fome de-^°"^^^* ^'*" ^"e conical metallic point, were heated to a higher 

 fcended. temperature than that at which they were difpofed to fink in 



ice-cold water; and thefe rofe and fpread themfelves over the 

 furface of the cold liquid; but others, which happened to 

 acquire lefs heat, defcended in it, and after filling the cork 

 cup, overflowed, no doubt its brim, and then defcending to 

 the bottom of the brafs cup, and coming into conta6l with 

 that ice-cold metal, were there cooled, and there remained 

 at reft. 

 Cork ag-^od As cork is an excellent non-condu6lor of heat, the warm 



non-conduaor. water accumulated in the cork cup during an experiment re- 

 tained its heat a long time after the heated ball was removed, 

 notwithftanding its being furrounded on all fides, and even co- 

 vered immediately by ice-cold water; (which by the by is a 

 pretty flrong proof that water is by no means a good condudor 

 Cautions* of heat) care however was taken, not only to remove this 



warm water after each experiment, by brufViing it away with 

 the foft end of a ftrong feather or quill, but alfo to cool the 

 cup, and reduce it to the temperature of freezing water; 

 which lafl operation was found to be much accelerated by 

 brufhing it out frequently with the feather. In order that this 

 feather might itfelf be ice-cold, it was fuffered to remain con- 

 ilantly in the ice-cold water, in the cylindrical vefl!el. 

 Apparatus by I mufl not forget to give an account of the means ufed for 



which the cone fixing the metallic ball in its place. This was done in a very 

 fimple and efFedtual manner. A flip of firong tin (G H) fix 

 inches long, and 2| inches wide, with a circular hole in the 

 middle of it, one inch in diameter, being laid horizontally on 

 the top or brim of the cylindrical veflel, in fuch a manner that 

 the center of that circular hole coincided with the axis of the 

 cylindrical veffel, the fliort cylindrical projection belonging to 

 the ball being introduced into that hole, the ball was firmly 

 fupported in its proper place. 



The quantity of ice-cold water in the cylindrical veffel was 

 fo regulated that the whole of the conical point being fub-r 

 merged, the furface of the water was on a level with the lower 

 end of the cylinder, or, which is the fame thing, with the 

 bafe of the inverted cone. 



4 When 



was fixed. 



