58 EFFECTS OF WINDS AND OF 



The following set of observation equations for August 5, 1910, at Buffalo, 

 serves as a typical example. They are a part of solution W25, which included 

 in all 470 such equations, covering 500 hours out of 22 selected days. 



Wind Observation Equations, Buffalo, August 5, 1910, Solution W%5. 



1 a.m - 33Cp- 6C a -29 = t;i 1 p.m -150C p -100C a +20 = t>u 



2 - 6Cp- 24C a + 14 = W2 2 -lOOCp OC a + 8 = i- u 



3^ - 47C P - HCa +31=^ 3 OCp- 33C a - 5 = t>u 



5-6 - 12C P - 24C a +32 = t> 4 4 - 33C P - 83C a + 2 = vu 



7 OCp OC a - 3 = t-6 5 - 83C P + 



8 OC P + 24C a -16 = fe 6 + 83C P - 



9 + 24C P - 48C a -U = v, 7 - 42C P + 



10 - 48Cp- 70C +23 = i>8 8 + 75<7p+374C a + 2 = 



lla.m - 70Cp-160C a -21 =v, 9 +374 



N -160Cp-150C +22 = zJio 10 +154Cp+ 



11 p.m + 59C P - 



M - 59C P - 12C +ll=t' 22 



The unit used in expressing L, the absolute term, is 0.01 foot. 



The basis on which such combinations as are indicated for 3 and 4 a.m. 

 and 5 and 6 a.m. were decided upon will be indicated later in connection 

 with the discussion of the accuracy of the computed wind effects. The basis 

 for certain rejections which were made will also be indicated later in the 

 same place. 



Table No. 11, which follows on page 59, shows how the coefficients of 

 C p and C a were computed. 



The wind velocities and wind directions as shown in the second and 

 third columns of table No. 11 were observed at Buffalo by the Weather 

 Bureau. 



The values in the second column, wind velocities in miles per hour, are the 

 values of h from which the fourth column of table No. 11 was computed. 



The values of S& shown in the fifth column were taken from table No. 10 

 for the observed wind directions at Buffalo as shown in the third column. 



Each value in the sixth column is the product of the values shown on the 

 same line in the fourth and fifth columns. 



Each value of the coefficient of C p as shown in the seventh column is the 

 difference, in the sense (preceding current), of the values shown on two 

 lines in the sixth column. Similarly, the coefficient of C a as shown in the 

 last column of the table is the difference of two values in the sixth column. 



A comparison of the seventh and eighth columns of table No. 11 with the 

 coefficients of C p and C a in the example of observation equations will make 

 the relation clear. Note that in the combined equation for the two hours 

 3 and 4 a.m. the coefficient of C p , 47, is the algebraic sum of the two values 

 for the coefficient of C p shown in table No. 11 for the hours 3 and 4 a.m., 

 namely, 24 and 23, respectively. In each such case the coefficient in a 

 combined equation is the algebraic sum of the corresponding coefficients 

 of the separate equations which were combined. 



