HTDIIOSTATICS. 107 



Del Cimento, at Florence, its absolute incompres- 

 sibility was thought to be proved. 



A globe of gold was filled with water, and ham- 

 mered violently ; but the water oozed through the 

 gold, and stood like dew upon the surface. Lord 

 Bacon had, however, tried the same experiment 

 with a globe of lead, and with a similar result ; but 

 he drew from it the opposite conclusion. 



Mr. Canton, about fifty years ago, made some 

 experiments which showed that water was com- 

 pressible in a very small degree : and Mr. Zim- 

 merman at Leipsic, in 1779, found that sea water 

 when inclosed in the cavity of a strong iron cylin- 

 der, and pressed by a force equal to a column of 

 sea water 1000 feet high, was compressed ?ie part 

 of its own bulk. 



It has already been stated that the cause of 

 fluidity does not appear to consist in the figure of 

 the particles, but in their want of cohesion. 



Different fluids have different degrees of tena- 

 city or fluidity, according to the facility with 

 which the particles may be moved amongst each 

 other. Water and mercury may be considered as 

 among the most perfect fluids. Others, as oil, 

 mucus, &c. are viscous or imperfect fluids. 



It is from the imperfect cohesion of fluids, that, 

 when in small quantities, they arrange themselves 

 in a spherical manner, and form drops. 



Although every one knows that all fluids have 

 weight, and gravitate when considered as a whole, 

 it being evident that a vessel weighs more when 

 full than when empty, yet, in the early times of 

 philosophy, it was an opinion that the parts of 

 fluids did not gravitate upon each other, and that 

 a portion of water lost its gravity when plunged 



