of Temperature for unequal length of Months. 377 
36°59 46:49 61°81 49°85 
38°60 53°13 61°01 ‘43°19 
41-50 59°11 56°39 39°30 
Taking as a standard the means previously obtained from the 
table of daily means, it will be seen that these approximate 
means for mean months differ from the true ones by only a 
Maximum error of ‘03 and an average error of ‘016. They 
_ Sive for the equation of the curve 
(Y= 48°91 
12°60 sin (e—111° 52’) —81 sin 2(¢~ 75° 35’)4-16 sin 3(2— 24° 8’) 
+'28 sin pee 40° 47')—°26 sin 5(z— 0° 50’) —-23 sin 62, 
previously deduced from the true means for mean months, ex- 
cept that e, is larger by 0° 1’; there are also some variations in 
30°18 48°65 74:88 54°56 
80°44 59°30 73°16 43°32 
38°28 68°30 65°78 33°52 
and the approximate means for mean months are found to be 
8 
30°56 '  §9°69 73-09 43°20 
8°68 68°59 65°63 33°45 
3 
The resulting equation of daily temperatures is for calendar 
onths 
=51°69 
22°75 sin (x—113° 28’)-"53 sin 2(7— 8° 37’) —-43 sin 3(x—5°) 
— °44 sin 4(a— 39° 26')—"17 sin 5(4—384° 31’)-+-°40 sin 62, 
and for mean months 
y=51°79 : 
22°75 sin (x—112° 42/)4°48 sin 2(r—_ 5° 52!) —-45 sin 3(a—4° 17’) 
— ‘44sin 4(r— 38° 35/)—°18 sin 5(z—33° 37')-++'41 sin 62, 
Showing an increase of ‘10 in the annual mean A, and showing 
a decrease of 0° 46’ in the arce,; this difference of are being 
almost exactly the same for New York as it is for Greenwich, 
Again, the means for calendar months at St. Paul are 
13°76 46:34 73°40 47-15 
17°57 58:97 70°05 31°67 
31°41 68°46 58°86 16°89 
Am. Jour. Sct.—Szconp Sxnims, You. XLI, No. 123—Mar, 1866. 
48 
