Hints for the formation of a Theory of the F.arth. :jci 



each other that a piece of paper will cover ninre than one 

 vibration node, ami will be thrown off by rubbinsr with the 

 bow, though they ought to remain } or the vibration will be 

 too weak, and not be fufficient to throw off the bits of paper 

 which ought to fall. 



III. Agenda, or a ColleBion of Obfervations and 'Refearches 

 the Refults of zuhicb may fcrve as the Foundation for a 

 Theory of the 'Earth. By M. De Saussure, 



[Continued from page 265.] 



CHAP. XIX. 



Refearches to he made in regard to Earthquaiet. 



T 



I. HE hiftorical part: the greatnefs, extent, and chro- 

 nology of their ravages in different countries. 



2. Does it appear that fome countries are more expofed 

 to them than others ; are there fome abfolutely exempted j 

 and how far is this connected with the local fituation of the 

 country ? 



3. To obferve the extent, duration, and direftion of ths 

 vibrations experienced by the earth when it fliakes. 



4. Are there any meteorological phenomena that an- 

 nounce or accompany earthquakes ; fuch as extraordinary 

 heat, calms, ftorms, movements of the barometer, electri- 

 city, vapours difperfed throughout the atmofphere, palenef* 

 or peculiar colour of the fun and (lars ? 



5. Other phenomena ; fuch as fubterranean noife, extra- 

 ordinary movement of the Tea, the watcf of fprings increafed 

 or dried up, any particular fmell, fymptoms of terror among 

 domedic animala. 



6. Are there any indications that fome earthquakes majf 

 have Iieen the effc<?ts of eleilricity, and that fuch convuliions 

 might be prevented by conduttors ? 



7. Are there not fome alfo which immediately depend on 



fubterranean- 



