172 NOTES ON METEOROLOGICAL OBSERVATIONS AT PLYMOUTH. 



(Beaufort Scale). Cloud: Form, Amount (0 — 10). Eainfall. 

 Sunshine. Ozone (0 — 10). 



The barometer is of marine pattern (B. T. 59), reading to '002 in., 

 and hangs in an unused room with a north light. The height 

 of the cistern above mean sea level at Devonport Dockyard is 125'9 

 feet, as ascertained by levels from Ordnance datum mark, executed 

 by Plymouth Borough Engineer. The reduction of observations to 

 sea level is effected by tables, specially supplied by the Meteoro- 

 logical Office. 



The thermometers are exposed in a Stevenson screen of the 

 usual pattern, open below. A complete duplicate set of thermo- 

 meters is kept in readiness in case of accident. Observations are 

 made with Negretti and Zambra^s ozone tests, the papers being 

 hung in the Stevenson screen. 



The rain gauge is of Meteorological Office pattern, with circular 

 rim 8 inches in diameter. Height of rim above ground 0'62 foot, 

 above mean sea level 117"7 feet. 



The Campbell-Stokes sunshine recorder is placed on the roof of 

 the Laboratory, at the point where the eye observations of wind, 

 cloud, and weather are made. The instrument fits into a frame 

 mounted on an adjustable stage, so that it can be removed and re- 

 placed without further adjustment. The place of observation is in 

 lat. 50° 21' 49" N., long. 4° 8' 21" W., as determined by measure- 

 ments from the dial on the Breakwater, of which the position is 

 accurately laid down on the chart. 



The hours of observation are 9 a.m. and 9 p.m. local time, or 

 9 h. 16"5 m. Greenwich time. It was found impossible to take 

 regular daily observations with greater frequency. 



The ordinary routine work was begun on September 1st, and a 

 table showing the means for the month is appended to these notes. 



Mr. Merrifield has been kind enough to give me access to his 

 father^s meteorological records, and I hope to be able to discuss 

 them fully in a future number of the Journal. In the meantime a 

 few of the more obvious results may be of interest. 



The position of the observing station was in lat. 50° 22' 25" N., 

 long. 4 7' 16"5" W. From the commencement of the observations 

 the instruments were 90 feet above mean sea level up to July, 1873. 

 They were then removed to a new position, cistern of barometer 

 69 feet above mean sea level ; rain gauge 9 feet 2 inches above 

 the ground. The hour of observation was 8 a.m. till 1887, when it 

 was changed to 9 a.m. 



