Possible Lunar Influence upon the Velocity of the TVwcl at Kimhertey. 291 
Air Tide Features. 
There is a remarkable difference between tlie runs of the numbers in the 
different columns : 
(a) The seventh column (perigee and apogee together) shows principal 
maxima at lunar noon and near lunar midnight, a secondary maximum at 
moonrise replacing the moonrise minimum, and a definite minimum near 
moonset. There is, moreover, on the whole a definite fall of pressure from 
beginning to end of the lunar day. The range is '003 inch. 
(b) The mean perigee curve has its principal maxima before noon and 
after midnight, a secondary maximum at moonrise, and a curious asperity 
at XXIII. The general fall of pressure during the lunar day is pronounced. 
The range is nearly "005 inch. 
(c) On the other hand, the apogee curve shows on the whole a small 
general rise, with maxima a little after lunar noon and perhaps before lunar 
midnight. It has the asperity at XXIII, and some tendency to a secondary 
maximum at moonrise, neither very definite. The range is about "004 inch. 
(d) The noon perigee cui-ve shows a large general rise during the lunar 
day, with principal maxima after noon and after midnight. The secondary 
maximum at moonrise is plainly visible, and there are also signs of the 
asperity at XXIII. The range between moonrise and U.M.P. is about 
•007 inch, that from moonset to L.M.P. about -008 inch. 
(e) The midnight perigee curve shows a general fall during the lunar 
day, with maxima before noon and after midnight. The moonrise maximum 
is large and falls a little early. The asperity at XXIII is also large. The 
range is perhaps "003 inch. 
(f) Almost the only prominent cbaract eristic of the horizon perigee 
curve is the large general fall during the course of the lunar day. The 
maximum at moonrise is as large as it is on the noon and midnight curves, 
but the U.M.P. and L.M.P. maxima and the moonset minimum are almost 
evanescent, and the tidal effect consequently almost lost. 
(g) The small asperities — namely, that at XX on the noon perigee curve, 
at XIX on the midnight perigee one, and at XVIII on the horizon perigee 
one — are possibly accidental, and only the first of the three is reflected in 
the mean perigee curve. There is, however, an analogue at XXI on the 
mean apogee curve. These asperities may have some resemblance to the 
moonrise maximum. 
The displacement of the U.M.P. maximum forwards and backwards in 
time on the various curves is evidently largely a result of the general rise or 
fall of pressure level during the lunar day. 
Wind Analogues.* 
(a) A comparison between columns 7 and 8 is shown in the open- 
* See the second and third papers. 
