SABINE’S EXPERIMENTS. 51 * 
and to the level of the sea; the first of these reductions being computed by 
the usual and well known method, and the second on the consideration, un- 
modified, of the force of gravity decreasing as tne square of the distance from 
the earth’s centre increases. 
The height of the pendulum above the sea was estimated as is shown in the 
following detail. 
A station in Murray-street 75 feet East of Chapel-street, as appears in the 
survey of the city, is above high water 20. 8 feet 
The half rise of the mean tide between the Spee and neap, ; 
is estimated at a 
The rise from the station in Murray-street to the ground line 
of Columbia College estimated 14 
The pendulum above the zround line estimated 30 
Total height above half tide 67 feet 
Vibrations of the detached Pendulums at Columbia . College, New-York, Lat. 40° 42’ 43” N.; Ele- 
: vation 67 feet above high tide. 
Pendulum 3. 
Etsy r Corr. to Vibrations in 24 rae = Vib. in a m. sol 
1822, Barom. Vibrations in 24 Mean Npanseieraty hours at Temperat. elec Corrections iy: day, in araRGanTet 
hours. Temp. || 53deg. | 93 degrees. Buoyancy | Kievation the level of the sea, 
December | In. 2 is Temp. 53°. 
23, A.M./30, 1ia6it6. 15 |40.2 |15. 504186110 . 646 
» P.M-/30, 2686116. 172) 40. 25||5. 48 2/86110. 69 
24, A.M.|130, 4086118.652|34 = ‘||8. 17 |86110. 482 
u Noon|30, 4086117.892135.5 7.525/86110 . 367 
», P.M.|90, 4086117. 389136. 55||7.073186110. 316 
25, A.M.|30, 1286118.72 |33.25]/8.492)%6110 . 228 
» P.M.|30, 0086118. 439|34. 55/|7. 933136110. 506 
26, A.M./30, 0086119. 04 |32.8 |/8.686136110. 354 
» P.M./30, 18/86118. 875/33. 85/8 «234136110. 641 
Means, |30 , 21|86117. . 66||7. 456|86110 . 47 |G, 4180, 276]|s6117. 164 
