MADE AT MARIETTA, OHIO. 



21 





Mean temp, of 

 calendar months. 



Correction, 



Temperature of 

 average mouths. 



January 

 February 

 March. 

 April . 

 May . 

 June . 

 July . 

 August 

 September 

 October 

 November 

 December 









31°.41 

 34.00 

 42.14 

 53.04 

 62.25 

 69.58 

 73.25 

 71.54 

 64.56 

 52.08 

 42.16 

 33.58 



— 0°.02 

 +0.16 

 +0.42 

 +0.56 

 +0.25 

 +0.28 

 —0.06 

 —0.06 

 —0.12 

 —0.23 

 —0.10 

 —0.10 



31°.39 

 34.16 



42.56 

 53.60 

 62.50 

 69.86 

 73.19 

 71.48 

 64.44 

 51.85 

 42.06 

 33.48 









52.55 



The immbers in the last column are represented by the formula — 

 T= + 52°.55 + 21°.13 sin (e + 255° 01') + 0°.14 sin (29 + 302° 20') + O0.46 sin (39 + 124°) 

 the angle 6 counting from January 1st at the rate of 30° a month. According to 

 this expression the lowest temperature occurs January 15th (31°. 1 Fahr.), and the 

 highest temperature July 23d (73°.4: Fahr.) ; the annual range is 42°. 3. The an- 

 nual mean temperature is reached April 14 and October 15. 



The formula^ gives the monthly means as follows : — 



August; with August .25 of the first of September; with September .69 of the first of October; 

 with October .13 of the first of November ; and with November .56 of the first of December. 



In strictness a second correction is required for curvature on account of which the mean tempera- 

 ture, in any one month, does not correspond to the mean of the times. This correction is small, and 

 might, practically, be altogether avoided by subdividing the period in a greater number of parts, 

 thus taking, for instance, half monthly instead of monthly means. Independently of these correc- 

 tions, the number of terms retained ia Bessel's function must bear a certain relation to the number 

 of subdivisions of the period. 



It has been thought unnecessary to apply the second correction in our series of observations, such 

 a refinement not being demanded by them. 



* To show the variation of the quantities A 5, C^ B^ C^ etc., in the expression T=A + B^ sin 

 (e + Cj) + B^ sin (29 + Cj) + etc., with the geographical position, a few tabular results are here- 

 with appended. 



Locality. 



Latitude. Longitude. 



A. 



B,. 



C,. 



B,. 



C,. 



B3. 



c,. 



Marietta, 0. . . . 



39° 25' 



81° 29' 



52°.55 



21°. 13 



255° 01' 



0°.74 



302° 20' 



0°.46 



124° 



Geneva, N. Y. . 



42 53 



77 02 



47.06 



23.03 



246 35 



0.50 



80 51 



0.18 



121 



Brunswick, Me. 



43 54 



69 57 



44.50 



23.15 



248 45 



0.88 



258 00 



0.79 



225 



Port Kennedy, North Som. 



72 01 



94 14 



+2.02 



39.20 



249 05 



0.80 



256 56 



1.06 



275 



Port Foulke, Smith St. 



78 18 



73 00 



+ 6.06 



33.11 



242 14 



6.32 



119 03 



0.74 



318 



Van Rensselaer H'br, N. G. 



78 37 



70 53 



—2.20 



35.39 



251 43 



6.72 



69 47 



3.20 



17 



Locality. 



Tears of ob's. 



Coldest day. 



Warmest day. 



Eange of temp. 



Epoch of Mean Temperature. 



Marietta, 0. . . . 



39 



Jan. 15 



July 23 



42°.3 



April 14 



Oct. 15 



Geneva, N. Y. . 



15 



26 



" 24 



46.6 



" 23 



" 22 



Brunswick, Me. 



51 



18 



" 22 



47.8 



« 20 



" 24 



Port Kennedy, North Som. 



1 



19 



" 20 



79.4 



" 23 



" 22 



Port Foulke, Smith St. 



1 



Feb. 16 



" 15 



69.6 



" 22 



Nov. 14 



Van Rensselaer H'br, N. G. 



2 



March 1 



8 



67.9 



"" 29 



Oct. 12 



