448 
MR. BAILY ON THE CORRECTION OF 
nearly with the following set of experiments where the spheres are attached 
to the ends of the short rods. 
I next took away the lower rod from the spheres, and they were then at- 
tached to the upper rod only ; whereby the pendulums became nearly of the 
same length as No. 3 and No. 6, mentioned in the preceding part of this paper: 
with the results of which it was my object to compare them. And as the 
3 inch brass sphere had not yet been swung with the iron wire, I now made 
some experiments with this mode of suspension, for the express purpose of the 
comparison*. The following are the results : 
Sixteenth set. — Results with spheres at the end of the short rods. 
Brass rod. 
Steel rod. 
Iron wire. 
Diameter 
of the 
spheres. 
No. 
n 
Weight 
of adhe- 
sive air. 
Weight 
due to 
sphere 
alone. 
No. 
n 
Weight 
of adhe- 
sive air. 
Weight 
due to 
sphere 
alone. 
No. 
n 
Weight 
of adhe- 
sive air. 
Weight 
due to 
sphere 
alone. 
inches. 
1-46 
60 
2-198 
1-047 
0-465 
63 
1-904 
0-537 
0-410 
3 
1-834 
0-457 
0-357 
2-06 
61 
1-901 
1-513 
1-078 
64 
1-785 
1-227 
1-104 
6 
1-751 
1-140 
1-040 
3-03 
62 
1-830 
4-202 
3-719 
65 
1-779 
3720 
3-587 
66 
1-748 
3-544 
3-444 
If the results with these brass and steel short rods be compared with those 
of the same spheres attached to the end of the long rods, stated in page 443, 
we shall find that as far as the value of n is concerned, it is, with one slight 
exception, greater in long pendulums than in short ones : but, the difference 
appears to depend chiefly on the relative magnitudes of the spheres and of the 
rods. With respect to the weight of adhesive air I regret that I could not 
conveniently swing these short rods without the spheres attached thereto ; 
which would have enabled me to ascertain (agreeably to the formula in page 
440), whether the weight of air adhering to, or dragged by, each sphere respec- 
tively is the same in this set of experiments, as in the preceding set. But, if 
we suppose that the weight of air, dragged by these short rods, is proportional 
to their lengths, and employ such quantities in the formula above mentioned, 
* The iron wire used with this heavy sphere was ‘023 inch in diameter ; or about one third of the 
thickness of the steel rod ; and nearly twice the thickness of the wire used in the experiments with 
the pendulums No. 1 to No. 20. It weighed 2G grains. 
