410 
MR. BAILY ON THE CORRECTION OF 
weighed 13019 grains: the specific gravity of the brass sphere and the screw 
I found to be 7‘995 ; and they weighed 9302 grains : and the specific gravity 
of the ivory sphere and the brass screw I found to be 1*747 ; and they 
weighed 2066^ grains. I shall designate these three spheres, as the 2 -inch 
spheres. 
No. 8 , 9 are the same leaden and ivory spheres as No. 5 and 7 '• but 
the vibrations, instead of being made on the knife-edge above men- 
tioned, were made by causing the wire to pass over a steel cylinder 
about one fifteenth of an inch in diameter, in a manner somewhat 
similar to that adopted by M. Bessel in some of his experiments. 
The wire used with the leaden sphere was the same iron wire as in the 
former experiments : but that used with the ivory sphere was fine silver 
wire, rather thicker than that used with No. 4, and weighed 2 grains. 
The experiments made with these spheres, and with this mode of sus- 
pension, are not (I fear) entitled to much credit ; for reasons which I 
will presently explain. HP 
No. 10 is a solid brass cylinder 2*06 inches in diameter and 2-06 inches 
high ; in order to correspond in dimensions with the brass sphere. It was 
tapped with a screw-hole on its flat side ; and was supported by the same iron 
wire and knife edge as above described. Its specific gravity, with the screw, 
I found to be 8T74 ; and they weighed 14190 grains. 
No. 11 is the same solid brass cylinder, tapped with a screw-hole on its 
circular side : but, as it was liable to turn on its axis when suspended by 
the iron wire, I was obliged to support it with a rod, or piece of thick brass 
wire, 0T85 inch in diameter, and 3 7| long; the upper end of which 4 . 
was attached to the knife edge above mentioned, on which the 
whole vibrated. The rod weighed 2050 grains, and its specific 
gravity was somewhat greater than that of the cylinder. The 
computed specific gravity of the whole was 8 * 202 . This pendulum 
was swung with its cylindrical side opposed to the line of its motion. 
No. 12 is the same solid brass cylinder, supported by the same 
brass rod, and in the same manner as in the preceding case, except 
that it was now swung with its flat side opposed to the line of its 
motion. 
No. 13 is the same solid brass cylinder, supported by the same 
ill 
