1 76 The Principles of Part IV* 



ftrated the fact to the eye, by feveral experi- 

 ments, in which a part of a branch, being 

 cut at both ends, and having its under part 

 immerfed in water, a moifture was imme- 

 diately perceived in its upper part. This 

 effect of capillary tubes muft arife from the 

 attraction betwixt the fubflance of which 

 they are compofed and water. 



THE attraction betwixt wood and water 

 appears to be very ftrong, by an experi- 

 ment related by Dr. Taylor, In the Philofo- 

 phical Tranfatfions, N 368. He hung at 

 a pair of fcales a piece of fir board, foak- 

 ed it in water, weighed it, and then im- 

 merfed it again in water. To raife this 

 piece of wood, which had a furface of 

 an inch fquare in contact with the water, 

 fifty grains over and above its former 

 weight were required. The additional 

 weight in the different trials, he fays, was 

 always proportional to the furface. The 

 diftance of the under furface of the board 

 from the furface of the ilagnating water, 



at 



