64 



MR ROBERT COCKBURN MOSSMAN ON 



as the values from 1769 to 1853 were, with the exception of those taken by Playfair* 

 from 1794 to 1799, entirely unreduced and uncorrected. There were thus the accumu- 

 lated data of eighty years awaiting discussion. As the work of reduction proceeded, 

 it became evident from the numerous anomalies and discrepancies disclosed by an 

 inspection of the monthly means, that the preparation of monthly isobaric charts for 

 Scotland must be attempted for the greater part of the first fifty years covered by 

 the investigation, with a view to the elimination of discordances. In this connection 

 the numerous manuscript observations kept at various places in Scotland, and kindly 

 lent by the Koyal Society of Edinburgh and the Scottish Meteorological Society, proved 

 of the highest value. 1 have specially to thank Dr Buchan for placing a large mass of 

 material at my disposal. 



The following are the additional stations whose data were utilised in the prepara- 

 tion of the monthly isobaric charts, the values for Edinburgh being calculated from 

 Registers III., IV., VI., VII., X., XL, XIV., XVI., XVIL, XVIII.t 



Kept at. 



Years. 



Hours of Observation. 



Remarks. 



Selkirk,. . . ■ . 



1769-1780 



1 



The means were collected by Hoy and 

 are contained in his MS. registers. 



Kirkcaldy, 



1775-1778 



8 a.m. and noon. 



Means calculated from MS. 



Branxholm, 



1774-1783 





Trans. Roy. Soc. Edin., vol. i. p. 204. 



Glendoich, . . . < 



1783-1801 ) 

 1810-1816 j 



9 A.M. 



Means calculated from MS. 



Gordon Castle, 



1781-1827 



8 A.M. 



Jour. Scot. Met. Soc, vol. v. p. 73. 



Dunfermline, . 



1799-1826 



9 A.M. 



Means calculated from MS. 



Carlisle, .... 



1801-1824 



8 a.m., 1 p.m. and 9 p.m. 



Trans. Roy. Soc. Edin., vol. xi. p. 429. 



Kinfauns Castle, 



1811-1834 



8 a.m. and 10 p.m. 



Means calculated from MS. 



Lasswade, 



1828-1843 



8 a.m. and 10 p.m. 



Means calculated from MS. 



Dollar, .... 



1836-1842 



9.15 a.m. and 8.30 p.m. 



Means calculated from MS. 



Aberdeen, 



1829-1841 



8 a.m. and 9 p.m. 



From Abstracts given in Aberdeen 









Journal. 



Much labour was expended in ascertaining approximately the instrumental error 

 of the above instruments, and in their reduction to 32° and sea-level, the height above 

 the sea being known in each case. The values from the above stations were then 

 entered month by month, on small maps of Scotland. The entries include the following: — 



1. The mean barometric pressure corrected and reduced to sea-level, and corrected 



for instrumental errors. 



2. The rise or fall of pressure from the previous month. 



3. The rise or fall of pressure from the corresponding month of the previous year. 



4. The prevailing wind at Edinburgh and such places as observed the wind 



direction. 

 The monthly means had also corrections applied to them so as to bring them to the 



* Trans. Roy. Soc. Edin., vols. iv. p. 213, and v. p. 193. t Tram. Roy. Soc. Edin., vol. xxxviii. pp. 682-683. 



