378 E. L. DeForest on Correcting, etc. 
and for mean montlis they are 
73°44 46:97 
17-79 59°41 69°93 31°50 
32°05 68°73 58°68 16°79 
The ps of the curve is found from calendar months to be- 
y= 44 
+29" ae sin wea 27") 4+-1°82 sin 2(2— 55° 28’)-+-91 sin ye 23’) 
+88 sin4(z— 0° 24’)— °74 sin 5(x— 28° 58’)-4-21 sin 6 
and from mean months it is 
y= 44°66 
+-29°86 sin (7—104° 41’)-++-1°93 sin 2(a — 55° 26')--" hy sin me pie tb 33’) 
— ‘84sin 4(r7— 44°54/)— *77 sin 5(w7—28° 40’)4"22 
Thus the corrected curve increases the annual mean re by ‘12 
ne bsg Dak the arc e, 
e Charleston observations give the following means for 
aisada months; 
50°36 65°44 81°72 67°88 
52°41 73°42 80°94 59°56 
58°68 79°01 76°89 §2°51 
and reduced to mean months they are 
8 67°76 
52°51 73°69 80°90 59°47 
58:97 79°16 76°78 52°46 
The equation of the curve is for calendar months 
y= 665 
16-07 sin (e7—109° 21") 4-86 sin 2(7—34° 24’)—15 sin 3(a—55°) 
+ :29sin4(e— 44° 10’)-+-09 sin 5(ex— 7° 1/)+482 sin 62, 
and for mean months it is 
y=66°63 
1 re sin (7— 108° 35’)-+'88 sin 2(a—35° 41/)—-13 sin 3(27—54° 6’) 
+ ‘3lsin 4(a— 44° 17')4-09 sin 5(x— 5° 22')4--33 sin 62. 
Here the annual mean A, is increased by ‘06, and the are ¢, di- 
minished by 0° 
The diminution of e, is therefore almost exactly the same at 
Greenwich, New York, St. Paul, and Charleston. The coef 
cient A, is nowhere eat tent by changing from calendar 
to mean months. will be found that the increase in the an- 
am eats a nearly constant ratio to A,. This ratio 
is 00404 for Greenwich, -00436 for New York, -00396 for St. 
Paul, and “00884 for Charleston. ‘The mean n of the four ratios 
405. It may therefore - Pasir that if we have for the 
aie of any place the equat 
ia. sin (z—e,) 
obtained on the supposition that the calendar months are of 
