S4 



MR ROBERT COCKBURN MOSSMAN ON 











Black Bulb in Vacuo. 





Bright Bulb on Grass. 









Excess over Shade 







Minus difference 









M 



IX. 







from Shade. 



Maximum. 



Mean. 



Mean. 



Greatest. 



Minimum. 



Mean. 



Mean. 



Greatest. 



January, 



84-5 



56-1 







13-8 



45-2 



7-5 



29-4 



4-3 



10-7 



February, 







103-3 



70-3 



26-7 



61-4 



7-0 



29-3 



3-8 



10-6 



March, . 







115-0 



84-6 



38-5 



76-8 



17-3 



30-6 



4-1 



12-2 



April, . 







129-0 



96-6 



44-3 



65-7 



20-0 



33-9 



4-2 



12-0 



May, . 







133-0 



107-5 



48-5 



67-7 



27-2 



39-5 



3-8 



12-6 



June, . 







139-3 



111-1 



47-7 



71-0 



31-3 



45-2 



2-8 



11-1 



July, . 







137-9 



111-2 



46-6 



69-5 



34-3 



47-8 



2-6 



8-5 



August, 







134-0 



111-0 



46-6 



67-2 



33-3 



47-7 



3-3 



8-9 



September, . 







126-5 



99-5 



39-1 



60-4 



28-1 



43-4 



4-2 



8-8 



October, 







112-5 



82-3 



30-1 



52-9 



21-2 



36-0 



4-6 



10-2 



November, . 







103-5 



64-9 



17-4 



48-9 



19-3 



33-4 



4-8 



9-7 



December, 







82-0 



51-8 



8-6 



32-0 



8-7 



30-2 



4-5 



12-4 



Year, . 







139-3 



87-2 



34-2 



76-8 



7-0 



37-2 



3-9 



12-6 



Reduction of the Observations taken in Edinburgh, from June 1731 to May 1736. — 

 (The observations are given in extenso in Medical Essays and Observations, vol. i. to 

 v. Edin., 1748, 3rd ed.) 



This register seems to have been kept with much care and regularity. The observa- 

 tions were made twice a day, the first nearly always at 9 a.m., the second between 2 

 and 7 p.m., but as a rule either at 4 or 5 p.m. The observations made include readings 

 of pressure, humidity, temperature, wind direction and force, and a condensed state of 

 the weather at the time. The daily rainfall was also measured from June 1731 to May 

 1735. The observations, it may be remarked, are adapted to the Julian or old style. 



Pressure. 



The barometer is described as a simple portable one, with a tube about a fourth of 

 an inch in diameter. The scale was probably of wood. The instrument was kept in a 

 chamber at a height of 270 feet above the level of the sea, the height being determined 

 experimentally by carrying the instrument to the sea-shore during an anti-cyclonic 

 period. The values given in the Table below have been corrected and reduced to 32° 

 and sea-level. There was no attached thermometer, but a mean value of 60° was 

 assumed, and the corrections for reducing observations made with instruments having 

 wooden scales applied.* The values may be looked upon as tolerable approximations. 

 The mean annual pressure was 29877 inches. The highest mean pressure was 30 # 204 

 inches in May 1733, and the lowest 29'530 inches in January 1736, showing a range of 

 674 inches between the mean monthly pressures. 



* Si nil in. nd's Meteorological Tables, p. 23. 



