Scales of Seismic Intensify. 51 



2. The damage to masonry or brick buildings universal and 

 often serious, amounting in some eases to destruction. 



3. All, or nearly all, brick buildings damaged. 



4. The earthquake universally felt, severe enough to dis- 

 turb furniture and loose objects, but not to cause damage 

 (except in a few instances) to brick buildings. 



5. The earthquake smart enough to be generally noticed, 

 but not severe enough to cause any damage. 



6. The earthquake only noticed by a small proportion of 

 people who happened to be sensitive, and, being seated or lying- 

 down, were favourably situated for observing it. 



(12) Scale used in studying British Earthquakes. — The scale 

 which I have used in studying British earthquakes differs but 

 little from the Rossi-Forel scale. The number of tests in each 

 degree is reduced to one in nearly every case, thus allowing 

 the isoseismal lines to be drawn with greater accuracy than 

 is attainable in a less thickly-populated country, in which single 

 tests might be seldom applicable. In districts which are 

 visited by destructive earthquakes, two additional degrees, 

 corresponding to degrees 9 and 10 of the Rossi-Forel scale, 

 would be required. 



1. Recorded only by instruments. 



2. Felt only by a few T persons lying down and sensitive to 

 weak tremors. 



3. Felt by ordinary persons at rest, not strong enough to 

 disturb loose objects. 



4. Windows, doors, fire-irons, &c. made to rattle. 



5. The observer's seat perceptively raised or moved. 



6. Chandeliers, pictures, &c. made to swing. 



7. Ornaments, vases, &c. overthrown. 



8. Chimneys thrown down and cracks made in the walls of 

 some, but not many, houses in one place. 



9. Chimneys thrown down and cracks made in the walls of 

 about one-half of the houses in one place. 



Comparison of different Scales. — In the following Table I 

 have endeavoured to express the degrees of different scales in 

 terms of those of the Rossi-Forel scale. An asterisk affixed 

 to the name of a scale indicates that the correlation given is 

 due to the author of the scale himself. 



E2 



