Ivlii Introduction to the Makerstoun Observations, 1843. 



No correction lias 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 exjjosure ; 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 E,. 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 6, 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 y, whose axle rests on friction-rollers at g and A, ; « is a spiral which has a 

 cord wrapped on it carrying a weight h, which balances the vessel e; Z is a dial, 

 graduated on the face near the circumference ; m an index, attached to the common 



