26 J. D. Everett on Reducing Observations of Temperature. 
as in the arithmetical example below; and EH, and A, are ob| | 
tained by the oe | 
tan E, = a 1 yA gt ohok' + Qi, or using EH, as a subsidi- 
ary angle, A; =.Q,, sec By. ; 
To find P, and Q,, proceed as under. | 
Ree) By =U 
Let ¥, = eee a z 4 s. i. ; 
41 oe ee K, eK —S,)=L, 
YotYs = K. ( s) x(= 1) | 
Yst¥o =K;- (Ky +K,) X So = My 
Ya T Yao — Fa (K,+K,) x 8,=M, 
ve ere hs (K,-+K,) xX S,=M, 
Then will t, Rs = we: 
M,+M,+M,= 
whence EH, and A, can be obtained by the equations 
tan E, = Pe A= Q, sec E.. 
Qe 
To find P, Q,, P, and Q, we have 
hoth,—kp=6P,  Ky+K,—HK,+K,+5, +K,)=6P, 
Rbk Fe Oe (Ent Ke— Ma H) XS = 60, 
whence EH, A, and A, can be obtained as aia 
In the ling exa mie the values of P,,Q,, E, and A,, 
are found for H on the assumption that the mean 
temperatures of cuiaadae months, may be regarded as iden- 
tical with the temperatures of 12 equidistant points in the year. 
The numbers in the first column are the mean temperatures of 
the months January to June, those in the second column are t 
mean panto nie of the months July to December. 
i. IL. Til. ee cone VE Ve 1s pee 
(L—IL) | in pitria (ITI—LV,) (VX VL) |\(IT+TIV.) jz IX.) 
23-9 | 64°9 | —41°0 —41°0 | Ss | —41:00 || —41°0 | Sy “00 
23°2 | 65:1 | —41°9 | -+-30 | —72°5 | S,| —62-79 || —113 | S;| — 5°65 
801 |. 58:3 rag +105 | —38-7 8, —19°35 || —17-7 | S,| —15°33 
389 | 48-2 — 93 | 8, 00 9831S, | — 930_ 
483 | 878 Ks¢- ; 6 T2314 6 — 30°28 
584 | 27°8 0°6 Siete 
Bey P= = 2052||  Q= |= 505 | 
E, = tan" gi = 76°10, A, = Q, sec E,y=—21°14. 
The coefficients A,, E, and those belonging to higher terms — 
are aehy comparatively little practical use, and it will not be neces: 
to append examples of the process | for ae them, 33 
thane no difficulty in the application of the form 
