28 REPORT—1852. 
The total amount of rain, at the several stations, for the year 1851, is as follows :-— 
Station. Rain in inches, 
Portarlington..... =Rhnaos 21°2 
20-25 { Kitlough oe iin weve 23°2 
Dublin ...... cbuésoeuswen ee OS: 
SA iv aNesaesatds ene see wees GOAT 
aeoaee Donaghadee ............ 27°9 
Courtown ......06 Poste: 29°6 
ACPD (adc ceo ccinastec'e's dae ORO 
Armagh ...ccececsseseoees 33°1 
30-359 Killybegs ssss-cssseesss 33°2 
Dunmore ....sccceseeess 33°5 
‘ IPGEEDUSN) Feacseessuicanies 37°2 
35—40 { Buncrana ...cecscceeeees 39°3 
Markee... adac deactsensess 40°3 
BPS { Castletownsend......... 42°5 
45—50...Westport ..seeeeereeeees 45°9 
50—60...Cahirciveen ......... aoe 59°4 
It will be seen from the foregoing table— © 
1. That there is great diversity in the yearly amount of rain at the different sta- 
tions, all of which (excepting four) are but a few feet above the sea-level; the 
greatest rain (at Cahirciveen) being nearly three times as great as the least (at 
Portarlington). 
2. That the stations of least rain are either inland or on the eastern coast; while 
those of greatest rain are at or near the western coast. 
3. That the amount of rain is greatly dependent on the proximity of a mountain 
chain or group, being always considerable in such neighbourhood, unless the station 
lie to the N.E. of the same. A 
The author illustrated this last position by reference to the map prepared by 
Captain Larcom, at the instance of the Land-tenure Commissioners, in which degrees 
of elevation, differing by 250 feet, are distinguished by different shades of colour. 
Thus, Portarlington lies to the N.E. of Slieve-bloom, Killough N.E. of the Mourne 
range, Dublin N.E. of the Dublin and Wicklow range, and so on. On the other 
hand, the stations of greatest rain, Cahirciveen, Castletownsend, Westport, &c. are 
in the vicinity of high mountains, but on a different side. 
If we assume the proportion of rain at the different stations to be constant, or 
nearly so, the preceding numbers may all be reduced to their mean values by multi- 
plying by the factor, which expresses the relation of the rain of 1851 to the mean at 
any one station. The following table gives the yearly fall of rain in Dublin for the 
last eleven years :— 
Year. Rain in inches. Year. Rain in inches. 
SA toeeewusin civs'sejs 27°05 NS Aecsccaccacree 25°80 
TGs cc che ceases 28°08 TEAS D esanscavemun 34°11 
GES ee ceivcesrasias PA rp SAO Ree eect cones 29°80 
SAA. cwesesecscies 28°38 TSSOP, ccoaesecuaen 24°16 
1s Va eaingede pastas (OU NSDilteveasuraewcete 26°40 
SAG ada cccdes sac 36°09 — 
Mean.... 29°01 
On this assumption, therefore, the mean yearly rain at any station will be found 
: ; : 29°01 
by multiplying the number of inches which fell in 1851 by 1°1 (=iea0)- The 
greatest mean monthly fall of rain in Dublin occurs in October, and its amount is 
3°34 inches; the least mean monthly rain is in February, its amount being 1°74 
inches. 
The last point adverted to by Dr. Lloyd, as deduced from these observations, was 
the evidence which they afford of the frequent occurrence of cyclonic movements in 
the atmosphere. The observations being simultaneous at all the stations, such 
movements are at once detected by a comparison of the directions of the wind at the 

