Meteorological Observations at Hudson, Ohio. 267 
have added for comparison three years’ observations at Cam- 
bridge, and two years’ observations at Toronto. 
Hudson, . . : 28-808 
Reduction for 1141 feet, ‘ } + 1-222 
Correction for gravity, ; : —-010 
Zero error, : . ; + .007 
30-027 
Cambridge, - : 29-940 
Reduction for 50 fodl? : : +055 
Correction for gravity, : - — ‘007 
29.988 
Toronto, . - : 29-608 
Reduction for 342 ea, A ; +378 
Correction for gravity, “ : — 004 
Zero error, ‘ : : — 004 
29-978 
Comparing these results with those given in my former article, 
we have— 
Hudson, . ‘ : : 30:027 
Cambridge, ‘ j ” 29-988 
Toronto, . ‘ é ‘ 29:978 
New York, d ‘ ‘ 29: Sr 
Montreal, . : s , 29-989 
Quebec, . ; : * 29:919 
The excess of pressure at Hudson is remarkable, and indicates 
a probable error in the assumed elevation of the place. If we 
suppose the elevation to be 1092 feet, the resulting pressure will 
be 29-983. ‘This gives an error of 50 feet in the assumed eleva- 
tion of Hudson, which seems hardly admissible; nevertheless 
that result (1141 feet) was derived from an imperfect connexion 
with a hasty rail-road survey from lake Erie. 
It has been justly remarked by Colonel Sabine, that the oscil- 
lations of the barometer are the complex effect of changes in the 
pressures of the vapor and of the gaseous atmosphere ; and that 
while we confine our attention to this complex effect, we fail to 
detect the causes of the phenomena. But as soon as we separate 
