140 Scientific Proceedings, Royal Dublin Society. — 
11 p.m., and 8 a.m. each day; and hourly observations from the 
tank. The temperature of the water in the tub was observed, 
but I have not been able to devise trustworthy observations of the 
temperature in either the tank or the Piche atmometer. More- 
over, hourly values of the temperature of the dry bulb, wet bulb, 
and dew-point are available, as well as those of the velocity of the 
wind, and the relative humidity. I have assumed that the mean 
temperatures of the various water-surfaces between 5 and 8 p.m., 
and between 8 and 11 p.m., is the arithmetic mean of the tem- 
peratures at 5 and 8 p.m., and at 8 and 11 p.m., respectively. A 
similar assumption would not be safe for the longer time intervals. 
The following are the means of the various temperatures :— 
Taste 1.—(114 days.) 
5 p.m. 8 p.m. 11 p.m. 8 a.m. 
PpenCup, (0) oe ele i705 63:6) fee aa Or? 58-0 
One-foot Pipe, : : 73°6 68°8 | 63°7 56°9 
Two-foot ,, ON 73-7 692 =| G45 57-4 
Three-foot ,, Nebr: 74-0 69-8 64:8 51:5 
Tita ne al 67-5 66-1 | 64-0)» | Manto ges 
gta Race Rate Semel alt Fra Me | BOS 62:3 
Taste 2—(15 days.) 
ll a.m. | 2 p.m. | 5 p.m. | 8 p.m. | 11 p.m.| 8 a.m. 
@peniCup, )e ) | > | (684 || 72-4) |) 70:9), | 163-8) assem 
Onestoot Pipe, | fe 64:4) | 72:8 | 74691) lse3's) a) ener se 
Two-foot ,, POSES ee Woes | es | sae 
Three-foot ,, 1) | 6476 9) 72:8 | 75-1) || 70-0 ||) 64291 aabes 
Tub, 2 fA 60:7" | “666” [67-6 66-0 9) esto mm mes 
ASEM ie eee te yee aN en ati bcd 79-9 75°8 | 64:7 59°5 60-3 
We see from this that the temperature of the air is at all times 
greater than that of the open cup; while it is greater than that of 
the three pipes and of the tub during the day, but less during 
the night. On the other hand, the temperature of the surface 
of the water in the tub is less than that of the three pipes during 
the day, but greater at night. 
