SECT. XX. 5. OF VERTIGO. , 273 



fomewhat longer, before he falls, ficknefs and vo- 

 miting are very liable to fucceed. But none of 

 thefe circumftances affect thofe who have habituated 

 themfelves to this kind of motion, as the dervifes 

 in Turkey, amongft whom thefe fwift gyrations 

 are a ceremony of religion. 



In an open boat palling from Leith to Kinghorn 

 in Scotland, a fudden change of the wind fhook 

 the utidiftended fail, and flopt our boat ; from this 

 unufual movement the paflengers all vomited ex- 

 cept myfelf I obferved, that the undulation of 

 the (hip, and the inftability of all vifible objects, 

 inclined me llrongly to be fick ; and this continued 

 or increafed, when I clofed my eyes, but as often 

 as I bent my attention with energy on the manage- 

 ment and mechanifm of the ropes and fails, the 

 ficknefs ceafed ; and recurred again, as often as I 

 relaxed this attention ; and I am aflured by a gen- 

 tleman of obfervation and veracity, that he has 

 more than once obferved, when the veflel has been 

 in immediate danger, that the fea-ficknefs of the 

 paflengers has inftantaneouily ceafed, and recurred 

 again, when the danger was over. 



Thofe, who have been upon the water in a boat 

 or (hip fo long, that they have acquired the necef- 

 fary habits of motion upon that unflable element, 

 at their return on land frequently think in their re- 

 veries, or between ileeping and waking, that they 

 obferve the room, they fit in, or fome of its furni- 

 ture, to librate like the motion of the veflel. 

 This I have experienced myfelf, and have been 

 told, that after long voyages, it is fome time before 

 thefe ideas entirely vanifh. The fame is obfervable 

 in a lefs degree after having travelled fome days in 

 a ftage coach, and particularly when we lie down 

 in bed, and compofe ourfelves to fleep; in this cafe 

 it is obfervable, that the rattling noife of the 

 coach, as well as the undulatory motion, haunts 



us. 



