Iviii 
Introduction to the Makerstotjn Observations, 1843. 
No correction has been applied to the observations of the dry and wet bulb 
thermometers ; the observations of the maximum and minimum register thermome- 
ters have been corrected, and all the abstracts of results for the dry and wet bulb 
thermometers. 
§11. Rain-Gauges. 
89. The rain-gauge (A) is placed in a space, enclosed by a paling on the top 
of the Observatory hill, with a good exposure on all sides. The funnel mouth is 
6*1 inches in diameter, 8 inches above the soil, and 218 feet above the level of the 
sea. The quantity of rain is measured at noon by pouring it into a glass tube, 
graduated with reference to the aperture of the funnel. 
90. The monthly results of two other gauges are given in the abstracts. One 
(B) is placed on the top of the greenhouse roof, 680 feet NNE. of the Observatory 
gauge ; the funnel mouth is 6*7 inches in diameter, it is connected with a graduated 
tube within the greenhouse, it is 18 feet from the ground, and 192 feet above the 
level of the sea. This gauge is sheltered to the E. and NE. by trees, and its indica- 
tions are therefore less trustworthy, especially during easterly winds ; the amount of 
rain received in the funnel is also affected by the gusts of wind deflected from the 
sloping roof. 
91. The other gauge (C) is in the middle of the Makerstoun garden, with a 
good exposure ; the funnel mouth is 6*7 inches in diameter, is 6^ feet above the 
soil, 171 feet above the level of the sea, and about 620 feet N. by E. of the Obser- 
vatory gauge. The funnel is connected with a graduated tube. The greenhouse 
and garden gauges were observed by Mr Macgall, the head-gardener. 
§ 12. Anemometer. 
92. The anemometer consists of two separate parts, both made and erected by 
Adie and Son ; one gives the direction, the other the pressure, of the wind. 
93. The vane is placed on the north wall of the Observatory, and, by means of 
a rod and geering-wheels, it indicates the direction of the wind on a dial-plate within 
the building. 
94. The anemometer proper, the invention of Mr It. Adie of Liverpool, is 
placed at the north-east corner of the Observatory. This instrument will be best 
understood by a reference to the annexed figure ; a is a cistern containing water to 
the level b, c being a turn-cock for letting the water off to the exact level, and d a 
glass gauge to shew when the water becomes too low, from evaporation or other- 
wise ; an inverted vessel e is suspended in the water by a cord passing over the 
wheel /, whose axle rests on friction-rollers at g and h ; i is a spiral which has a 
cord wrapped on it carrying a weight k, which balances the vessel e ; I is a dial, 
graduated on the face near the circumference ; m an index, attached to the common 
