ON REGISTERING EARTHQUAKE SHOCKS IN SCOTLAND. 87 



EARTHQUAKE SHOCKS. 



NATIONS. 



indicated by P ; thus, 4 o'clock in the morning would be marked in the Table 4 A ; 



afternoon, 4 P. 



and intermediate degrees of intensity by intermediate numbers ; thus, one half as violent or 



ferred to, to be entered 5. 



than first (which is almost always the case) the latter to be marked with a small c ; thus C c 



second weaker than the first. 



or all ; using the small letters here too to mark the relative force of each ; thus c H t 



and ending in a slight tremor ; and C H T, one such as that of Oct. 23, 1839, where all 



were intense. 



observer to proceed from, most needed in slight shocks that do not affect the instruments ; 



instrument enables the observer to ascertain it. 



tered only by those observers who have such instruments at hand. The strength of the 



and 10 for a hm-ricane ; and a cahn, 0. 



M, much, and L, little. 



Five minutes after 

 Shock. 



2 I 



g i 



other particulart not included in preceding list, that might be 

 considered as either directly or indirectly con- 

 nected with the shocks. 



29*6 



D L 



The direction and dip in this case (10. 40. A) given most distinctly by spiral 

 pendulum in steeple. The horizontal force one in Post-office attics ranged 

 fully half an inch. Day cloudy, cold and showery. Close rain from 2 to 

 4i r. ; mostly fair afterwards. Next day (28) cloudy with occasional sun. 

 shine ; much thunder at 2 P., and cloudy with light rain afterwards. 



Other three slight shocks observed by some during the night between the 1st 

 and 2nd ; rain in morning of 2nd ; light, cloudy, mild, moist and warm day. 



Fine harvest morning ; splendid dry fine night. 



.Morning cloudy; day also ; with occasional blinks of sunshine. 



Day dark; drizzlii)g rain occasionally. This shock observed only at Tomperran. 



Most dark and dull ; rain at night. 



Very dark morning ; much rain through the day. 



Very dark morning ; much rain through the day. 



Frosty, clear and sunshine. 



Dim and cloudy ; a fall of about 1 in. snow during the night ; a.m. sunshine ; 

 p.m. overcast. 



Very dark and overcast ; after lOi sleet and snow. 



In all 8 shocks to-day. During first 5 days bright and sunny. Barometer at 

 3 o'clock at 30-2 ; ext. thermometer 35. Wind gentle and S. W. all day. Spiral 

 in steeple indicated 3-8ths in perpendicular heaves ; no lateral mark. Hori- 

 zontal pendulum in Post-office attics indicated same amount of heaves as 

 spiral in steeple ; sand in glass had fallen 2 in. since last noticed ; but part of 

 this fall might have been owing to other causes, as it had not been marked 

 for a month before. 



Fine morning ; fine day and night. 



Severe frost; fine clear and dry day; night overcast. 



Dull morning ; showery day ; clear night. 



Clear sharp frost. 



Dull and snowy morning ; fine clear night. 



Fine morning ; afternoon dull, inclined to rain. 



Dull fogsy morning; fine day and night. 



Beautiful morning ; showery afternoon. 



Clear, fine day ; a little rain at night. 



Clear morning ; fine day ; rain at night. 



Dull morning; showery during day. 



Cloudy morning ; clourty and sun-shining day. 



Fine day ; a little cold towards evening. This shock observed only at Tomperran. 



Fine day. 



Fine day. This shock observed only at Lawers. 



