306 /PHILOSOPHICAL TBANSACTIONS. [aNNO J 765. 



fhoure, it had lost 26 grains more of its buoyant force, losing in the first 48 

 'hours 14, and in the 24 succeeding hours 2 grains only: from which it appears, 

 that after the rx)rk has been in the water for 48 hours, its absorption becomes 

 less than before, in proportion as 12 is to 1. This float having continued in the 

 water for 78 hours, each piece of cork, being wiped very dry on its surface, but 

 not squeezed, weighed as follows : 



N° 1 weighed 55 J Grains having gained 1 2 grains 



2 47 4j 



3 66 12 



4 69j H 



5 .. 51 J 8J 



All 5 weigh. o79j gained ^^ 



Being then desirous to know if any quantity of salt had insinuated into the 

 pores of the cork, and if so, how much ; the above float was hung up to dry in 

 a warm airy room, where it was not far from the fire, for the space of 48 hours: 

 when it seemed to be quite dry, and each piece being weighed, was found as 

 follows ; 



N<* 1 weighed 45 grains, the salt supposed to be contained was 3 grains. 



2 46 , 3J 



3 59 .". Pi'.-iV 6 



4 55 ...-. 2 



5 4+.. 1 



All 5 weigh. 249 salt gained 15j 



But on their being hung near a fire for 72 hours, until perfectly dry, no salt 

 appeared to be imbibed, for the above numbers weighed as follows; having lost 

 by extraordinary dryness about -^ of their first weight. 



N° 1 weighed 40 grains, having lost 2 grains 



2 42 4 



3 . . 54 3 



4 53 3 



5 43 3 



i;32 15 



Exper. 7. For the sake of greater exactness, another float (marked c) was 

 made of two cubes of cork, amounting to 164 grains; the larger 118, and the 

 smaller 46 grains; this was put into the same vessel of river water, after it had 

 been 96 hours in a warm chamber, and supported a medallion of lead weighing 

 766 grains; it was left in the water for 3d hours longer, and weighed again, 

 when it was found to support 754 grains, having lost 12 grains of its buoyant 

 force in that time of immersion. From this 2d experiment does it not appear. 



