Second Period {11 185°.0 „ {12 200°.0 „ {13 206°.1 „ {14 209°.5 „ {15 210°.7 „ {16 211°.3 „ {17 211°.5 Differences. „ {18 211°.5 0 „ {19 211°.5 0 „ {20 211°.5 0 „ {21 211°.5 0 „ {22 211°.4 –0°.1 = θₙ –0°.1 –0°.1 Third Period {23 211°.3 „ {24 211°.2 –0°.1 „ {25 211°.1 –0°.1 „ {26 211°.0 –0°.1 „ {27 210°.9 –0°.1 „ {28 210°.8 –0°.1 „ {29 210°.6 –0°.2 „ {30 210°.5 –0°.1 From the twenty-second interval, the regular fall of temperature begins and 211°.4 is therefore taken as θₙ. The mean temperature of the beginning period is therefore (162°.6 + 162°.9)/(2) = 162°.75 = t. The value of v is (162°.6 − 162°.9)/(10) = –0°.03. For the end period the value of t′ is (211°.4 + 210°.5)/(2) = 210°.95 and the value of v′ is (211.4 − 210.5)/(8) = + 0.11. Then the sum of the observations from eleven to twenty-one inclusive = Σ′_{n–1}θ = 2280.1 (θ₀ + θₙ)/(2) = 187.15 The sum = 2467.25 nt = 1953.00 Difference 514.25 This difference multiplied by v − v′ = 0.14 gives a product equal to 71.995 This product divided by t′ − t = 48.20 gives a quotient equal to 1.49 nv = –0.36 The sum = 1.13 = C