XCVl 



General Results of the Makeestoun Observations. 



Table 90. — Monthly Means of the Maximum Pressure of the Wind within lO^i at the Observation 



Hours for the Years 1843-6. 



Year. 



Jan. 



Feb. 



March. 



April. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Slean. 





lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



1843 



1-29 



0-87 



0-32 



0-49 



0-39 



0-40 



0-35 



0-17 



016 



0-42 



0-48 



0-72 



0-50 



1844 



0-34 



0-37 



0-52 



0-41 



0-20 



0-50 



0-16 



0-37 



0-34 



0-57 



063 



0-09 



0-37 



1845 



0-45 



0-52 



0-81 



0-61 



0-67 



0-56 



0-39 



0-38 



0-28 



0-63 



051 



0-97 



0-56 



1846 



0-48 



0-47 



0-61 



0-35 



0-54 



0-36 



0-49 



0-19 



0-18 



0-42 



0-46 



0-36 



0-41 



Mean 



0-64 



0-56 



0-56 



0-46 



0-45 



0-45 



0-35 



0-28 



0-24 



0-51 



0-52 



0-53 



0-46 



199. Annual Variation of the Approximate Mean Pressures of the Wind. — From the means of 4 years' 

 observations, the wind blew with the greatest mean force in January, and with the least mean force in Septem- 

 ber. The mean pressure, however, varies little for the six months October to March, while the sun is south 

 of the equator ; it is nearly constant for the three months, April, May, and June, diminishing gradually from 

 June to September. September is the month of least pressure in each year, excepting 1844 ; the month of 

 maximum pressure is more variable, January in 1843, November in 1844, December in 1845, and March in 

 1846. 



Table 91. — Variations of the Pressure of the Wind with reference to the Moon's Age and Declina- 

 tion for the Years 1843-6. 















After 













Moon's 

 Age. 



1843. 



1844. 



1845. 



1846. 



Mean. 



!Moon 

 farthest 

 North. 



1843. 



1844. 



1845. 



1846. 



Mean. 



d. d. 



lb. 



lb. 



lb. 



lb. 



lb. 



d. d. 



lb. 



lb. 



lb. 



lb. 



lb. 



14 16 



+ 0-03 



-0-16 



-0-09 



-0-08 



-0-07 



27— 1 



-0-06 



+ 0-32 



+ 0-06 



+ 0-05 



+ 009 



17—20 



-0-18 



+ 004 



+ 0-17 



+ 0-03 



+ 0-02 



2— 5 



-0-11 



-001 



+ 0.02 



-0-04 



-0-03 



21—24 



-0-06 



+ 0-18 



-0-01 



-0-03 



+ 002 



6— 8 



-001 



-0-02 



-0-10 



-0-01 



-0-03 



25—28 



+ 0-05 



+ 0-10 



+ 0-05 



-0-10 



+ 0-02 



9 12 



+ 0-02 



-0-07 



-006 



+ 0-08 



-001 



29 1 



+ 0-20 



0-00 



+ 0-17 



+ 0-07 



+ 0-11 



13—15 



+ 0-08 



-0-17 



+ 004 



-0-03 



-002 



2 — 5 



+ 0-07 



-0-08 



-003 



+ 0-13 



+ 0-02 



16—19 



+ 012 



-0-04 



+ 0-04 



-012 



0-00 



6— 9 



-0-04 



+ 0-04 



-0-07 



-001 



-002 



20—22 



+ 0-05 



-0-10 



-0-15 



+ 0-03 



-0-04 



10—13 



-0-08 



-0-15 



-0-15 



-0-01 



-0-10 



23—26 



-0-09 



+ 0-07 



+ 0-16 



+ 0-07 



+ 0-05 



200. Approximate Mean Pressure of Wind with Reference to the Moon'' s Age. — ^The mean result from the 

 first portion of Table 91 shews, that the pressure of the wind luas a maximum at conjunction and a minimum near 

 opposition. The result for each year shews a well-marked minimum near opposition, and a maximum near 

 conjunction. It has already been noticed (No. 194), that the diurnal range of the atmospheric pressure obeys 

 a similar law ; that is to say, for this argument, the diurnal oscillation of the statical pressure of the atmosphere 

 is a maximum when its dynamical pressure is a maximum. 



201. Approximate Mean Pressure of the Wind with Reference to the Moon's Declination, — ^From the last 

 column of Table 91, the mean result of 4 years' observations, it appears that the pressure of the wind is a maxiraum 

 when the moon is farthest north. Tliis result is shewn with some distinctness in each year, excepting in 1843, 

 for which the maximum occurs when the moon is farthest south ; there is, however, the appearance of a maxi- 

 mum near the time of the moon's farthest southerly position in the years 1845 and 1846 ; and, indeed, in the 

 mean for the 4 years ; it is probable therefore that the minimum pressui-e of the wind occurs when the moon 

 is near the equator. The same relation, between the diurnal oscillation of the statical pressure of the atmos- 

 phere and its dynamical pressure, holds as in No. 200. 



