OBSERVATIONS OF THE MAGNETIC FORCE. 
313 
Table XLIV. 
Station. 
Date. 
Dr. Locke. 
Lieut. Lefroy. 
Horizontal 
force de- 
duced at 
Cincinnati. 
Lieut. Lefroy. 
Total force 
at Cincin- 
nati tol-836 
at Toronto. 
Ratio of the 
horizontal 
force to 1 at 
Cincinnati. 
Inclination 
observed at 
Cincinnati. 
Horizontal force 
observed at the 
stations in the 
first column. 
Horizontal 
force ob- 
served at 
Toronto. 
Inclination 
observed at 
Toronto. 
70 26*2 
(1842.) 
(1842.) 
(1842.) 
New York ... 
1841. 
•8828 
1844. 
•8811 
70 25-0 
Mean 
•8819 
70 25-6 
4-008 
4-544 
3-537 
75 16-0 
1-791 
Cambridge 
1842. 
•8040 
70 26-2 
3-665 
4-558 
3-537 
75 16-0 
1-797 
r 
1841. 
•9175 
70 26-2 
Philadelphia . . < 
1842. 
•9178 
70 26-2 
L 
1844. 
•9151 
70 25-2 
Mean 
•9168 
70 25-8 
4-168 
4*546 
3-537 
75 16-0 
1-792 
Mean 
1-794 
Whence we have the total force at Cincinnati— 1-794. 
3°. Dr. Locke’s determination of the ratios of the horizontal force at Baltimore, 
Washington, Princeton, Newhaven, Albany and Sault St. Mary, to unity at Cincin- 
nati, and his observations of the Inclination at those stations, combined with the 
ratios of the total force to T836 at Toronto, determined by Lieut. Lefroy at the 
same six stations. The particulars of the comparison are as follows : — 
Table XLV. 
Station. 
Dates. 
Ratio of the 
horizontal 
force to 1 at 
Cincinnati. 
Inclination observed at 
Total force at Cincinnati to 
1-836 at Toronto. 
the stations 
in column 1. 
Cincinnati. 
By observations at 
the stations in 
column 1. 
Deduced for 
Cincinnati. 
Dr. Locke. 
Dr. Locke. 
Dr. Locke. 
Lieut. Lefroy. 
Baltimore 
1841. 
•9370 
71 34-1 
70 26-2 
1-782 
1-796 
Washington 
1844. 
•9483 
71 13-4 
70 25-0 
1-772 
1-795 
Princeton 
1844. 
•8833 
72 40-4 
70 25-0 
1-783 
1-794 
Newhaven 
1842. 
•8385 
73 29-8 
70 26-2 
1-773 
1-794 
Albany 
1844. 
•7876 
74 40-2 
70 25-0 
1-797 
1-800 
Sault St. Mary 
1843. 
•6695 
77 30-2 
70 25-5 
1-862 
1-796 
Mean 
1-796 
Whence we have the total force at Cincinnati =1'796. Collecting in one view the 
results of the three comparisons, we have — 
1°. By the direct comparison of the horizontal force at Cincinnati and 
Toronto, by Dr. Locke 1795 
2°. By three intermediate stations, at which the ratios of the horizontal 
force were determined by Dr. Locke to the force at Cincinnati, and by 
Lieut. Lefroy to the force at Toronto 1794 
3°. By six intermediate stations, at which the ratios of the horizontal force 
were determined to the force at Cincinnati by Dr. Locke, and the ratios 
of the total force to its value at Toronto, by Lieut. Lefroy .... 1796 
