8 
MR. H. M‘LEOD AND LIEUTENANT G. S. CLARKE ON THE 
158 X 486 = 76,788 lines passed in 158 revolutions. 
301 —199’5 = 101'5 lines between the two dots. 
101*5 — -5 = 101 lines corrected for movement of the wave. 
76,788 + 101 = 76,889 vibrations of fork in 5 minutes. 
76889 
" 300 
= 256"2966 vibrations per second. 
It frequently happens that the two numbers corresponding to the dots are on the 
opposite sides of the 0, in which case the counter indicates one more than the number 
of revolutions, and 486 must be added to the number corresponding to the first dot 
before subtracting the number corresponding to the second dot. 
The remaining entries in the note-book serve to show the whole of these cases. 
Mark 165 
166 
405-25 
268 
137-25 
+ -5 
137-75 
2 min. 
16°-9 
221 (counter) 
158 (at last experiment) 
30618 
137-75 
120)30755-75 
63 x 486=30618 
256-298 
Mark 167 407-25 407-25 
168 444-5 486 
893-25 
444-5 
448-75 
3 min. 
17°-0 
45684 
448-75 
316 
221 
95-1 = 94x486=45684 
180)46132-75 
256-293 
Mark 169 
170 
Mark 171 
172 
84 84 
258 486 
570 
258 
312 
- -5 
1 min. 
l7°-0 
15066 
311-5 
348 
316 
32 — 1=31 x 486=15066 
60) 15377-5 
256-292 
252 
464 
311-5 
252 
486 
4 min. 
17°-2 
61236 
274 
738 
464 
475 
348 
240)61510 
— 
— 
256-2916 
274 
127-1 = 126x486=61236 
256-297 
16*8 
256-298 
16-9 
256-293 
17-0 
256-292 
17-0 
256-292 
17-2 
5) 22 
5)34-9 
= 256-294 
16-98 
— 1"4 (correction for error 
of thermometer.) 
15-58 
